Sort of.  The new speakers do not use Sonosnet.  However, they can easily coexist on the same system with other speakers using Sonosnet, similar to what the Move and Roam have been doing for years.

Short answer...Correct. The Era series speakers do not join the SonosNet created by a Boost nor a speaker wired to your router. FYI, neither do the Sonos Roam or Move connect to the SonosNet.

Strange...didn’t see response by @jgatie a minute ago 

I have a mixture of speakers on SonosNet and the portables plus the new Era speakers which use the normal WiFi. All works great together

Thank you for the prompt response. So I only have two play:3 left which I am replacing with era 100 & 300. After which discontinue use of Sonos Boost?

You can actually discontinue use of the Boost now.  It has been optional for a while.

So no advantage anymore even if you don’t have the new Era speakers?

Thank you all for you’re time

I didn't say that.  In my opinion, Sonosnet has always had an advantage.