Beam as a computer speaker

No, this probably wouldn't be possible. Most computers just send a regular HDMI audio stream, but the Beam needs an HDMI-ARC audio signal instead. Unfortunately, they're not the same. Unless you have a computer monitor that happens to have HDMI-ARC (none that I know of do), or are using a TV with HDMI-ARC as your monitor, this probably won't be possible. Not to mention that, IMHO, it seems like it would be a bit large sitting on a desk. 🙂

What about connecting the Sonos Beam to the PC via the included Optical Audio Adapter?

there are HDMI to HDMI-ARC adapters offered e.g. http://a.co/9aE4P9Q but unknown quality/function/compatibility, you'd have to just try it.

Will let you know as I have the beam on order for just this purpose, luckily my mother board has an optical output for Audio, I was going to use a Playbar (a bit excessive i know) and 2 Play:1 but just as I was about to order I noticed on the web articles relating to the beams fcc filing so i held off until the announcement on the 6th June, glad i did as the Beam seems the best fit and should look and sound good mounted underneath the Acer x34a with the Play:1 as rears, this will allow me to disconnect the PC from the connectAmp so it can be used to power some out door speakers for the garden.

What about connecting the Sonos Beam to the PC via the included Optical Audio Adapter?

The question is also why would you want to use the beam as a computer speaker it makes almost no sense

The question is also why would you want to use the beam as a computer speaker it makes almost no sense
Maybe if you use your computer for watching TV or movies (many do) and/or for playing games (many do), and therefore need a low-latency device, but also want the convenience of a single multi-purpose smart speaker or already have a Sonos multi-room setup.

It's a bit of a compromise, but it's a real scenario for some.

an Update.
The Beam arrived a day early and i can confirm it sounds amazing, looks excellent, and fits in my own setup seamlessly as a 5.0 computer setup.

For myself, I have invested in Sonos equipement for the whole home/Garden, every major device that outputs Audio is connected and outputs via Sonos and is available through out the whole home except for my PC which is not your normal run of the mill PC but an extremely high spec PC used for Video and Photography retouching, also for the odd game or two.

Upto this point i used to have it connected via a Sonos ConnectAmp, outputing through some old small Cambridge Audio speakers that i Purchased in 1997 and the sound was good but was no where near as good as i would have liked so I stopped using it.

I connected my existing Playbar up as test with two play:1 for surround and was blown away by the difference as you would expect, and whilst it sat perfectly under the three monitors i use (1 x 34 inch curved ultra wide screen Acer x34a in the middle with a Illyama 24inch wide screen monitor in portrait mode on each side) obviously the Playbars size and power was still a little to excessive when your sitting about 1 to 2 feet away from the monitors.

The Beam however is the perfect size, and power output, Movies, videos and music played on the PC sound amazing as expected and Games come alive and are more immersive especially as i have Philips hue lights around the monitors which sync and change colour with the action in game play the same goes with Movies, Now using the Beam i have the sound quality and experience i was looking for, It looks amazing and compliments the whole PC setup, and with Alexa built in whilst not essential is a bonus.

I also got my Beam today and connected it to my computer. Agree with PaulRBoon that it sounds great. Bass is fine especially since you are so close to the speaker.

The only significant difference I experienced is that you can definitely hear the sound coming more from the center vs my previous speakers which were around 5' apart. So the soundstage is a little narrower which I expected.

Might get some 1s to expand the sound a little but since those can't be put on the "full" settings for TV (in this case computer) mode I don't know how useful they'd be.

Just thought i would share what the Beam looks like as part of a Computer 5.1 setup