I have been pondering about this. I have a couple of P1’s with ethernet connections providing a stable SonosNet that has just worked for many years, providing SonosNet to other non ethernet Sonos devices..
I would like to replace with ERA100’s and redeploy the P1’s to non ethernet locations, but I am slightly apprehensive about doing this as existing devices relying on SonosNet would be affected.
I don’t want to turn my support matrix from a nice green/yellow pattern, to a red/orange/white pattern 
I agree, I think it's a mistake too, time will tell.
Also, even when connected with adaptor, it's just then connected via ethernet, it's still not on Sonosnet. Other devices in the same vicinity can't connect to it like they can with Sonosnet.
I'm sure it's no coincidence a new WiFi strength tool is being added to App soon. I feel it will be used lots and the only solution, unlike now, where it can use Sonosnet, will be to somehow get an AP near (in itself often causes problems) or get ethernet to it….
Many ISPs now offer whole house WiFi using mesh systems, which will be the norm in a few years for consumers, so I assume this was the thought process for Sonos during their design phase. They also reduce the power consumption by removing SonosNet functionality, so there are some benefits. We just need to think ahead when planning changes to our own unique Sonos setups as we introduce ERA devices, in the same way from S1 to S2 setups etc.
Can I ask, with Mesh systems (I have a BT UK router), does this work OK with Sonos? Or are there issues?
To be clear, I don’t want a possible mesh BT WiFI disk for Sonos, just for a TV upstairs that has poor WiFI connection sometimes. Most of my Sonos is on SonosNet and my portable speakers seem to do fine on the WiFi.
If I got a BT Disk, could this upset Sonos?
Have just asked this in a new post, so as not to derail this post
Many ISPs now offer whole house WiFi using mesh systems, which will be the norm in a few years for consumers, so I assume this was the thought process for Sonos during their design phase. They also reduce the power consumption by removing SonosNet functionality, so there are some benefits. We just need to think ahead when planning changes to our own unique Sonos setups as we introduce ERA devices, in the same way from S1 to S2 setups etc.
Many of these more modern WiFi systems are designed to automatically switch networks for better performance. A good idea, unless you happen to have sonosnet running on a nearby channel and introduced dropouts.
Another consideration, from a general perspective, sonosnet means that your Sonos system is only as strong as it’s weakest link. If you created sonosnet to the router via a boost, for example, that means you’re trying to run hi res audio, atmos audio, possibly multiple streams, through a network device that was created long before these features were on track for future development. It also could mean that your old play:1 could have a more useful life as it won’t be expected to perform network functions beyond it’s original design.
This is on top of whatever Sonos may have planned for future features that may not be compatible with sonosnet.
Maybe that’s more relevant to Era 300 than Era 100, but it makes more sense to start making a clean break from sonosnet rather than slow down the transition even further.
Many of these more modern WiFi systems are designed to automatically switch networks for better performance. A good idea, unless you happen to have sonosnet running on a nearby channel and introduced dropouts.
Yet when those ‘smart’ networks start switching around channels and 2.4/5GHz, Sonos has had many problems with this too.
Another consideration, from a general perspective, sonosnet means that your Sonos system is only as strong as it’s weakest link. If you created sonosnet to the router via a boost, for example, that means you’re trying to run hi res audio, atmos audio, possibly multiple streams, through a network device that was created long before these features were on track for future development. It also could mean that your old play:1 could have a more useful life as it won’t be expected to perform network functions beyond it’s original design.
Sonosnet is very clever at finding ‘weak links’ and adjusting the matrix to suit and doesn’t generally need to be concerned with how far away from the router a device is. But if there is a weak link connected to the router, just connect another device to the router.
I have a Boost and several Sonos speakers and never had a WiFi connection problem ever…. until I got a pair of ERA 100’s. I keep losing one or other speaker in a stereo pair and sometimes shows both connected but only plays one channel. The point of wireless speakers is I don't want an ethernet connection or even £40 extra to pay for the dongle!
I have a Boost and several Sonos speakers and never had a WiFi connection problem ever…. until I got a pair of ERA 100’s. I keep losing one or other speaker in a stereo pair and sometimes shows both connected but only plays one channel. The point of wireless speakers is I don't want an ethernet connection or even £40 extra to pay for the dongle!
This sounds very familiar
I ended up returning the ERA’s and got a Sonos Amp, which works rock solid with a a pair of KEF Q150’s I had.
I will return my Era 100 for that exact same reason. 
. I wanted to upgrade my Play1… :(
