Sounds promising, will definitely keep an eye on it. Is it only on steam OS or are there plans to make it available on Ubuntu?
Also how do you see the space question, will you be playing mostly indies and small games on it, how will playing off an SD card impact the experience? I have a small nvme on my laptop and a large hard disk and it can be slow to get games going until I upgrade.
I don't use Linux myself so I may not be 100% on this but I believe the only way to use it is through Steam. So you download Steam on any version of Linux and it will allow you to play those games from it. You can also add "non steam games" onto the steam client and enable "Force Proton" and it will try to make the game work on Linux. The good thing about Steam OS is that the UI will look like a console UI so navigating and etc should be simple but you can also access a normal Linux desktop if you so choose.
You also have exclusive features like being able to Suspend games similar to a Switch which you can't do on Windows.
As for the space situation, I did pre-order the 512GB model but I don't plan to play AAA games on it. I mainly want to play more AA games like Scarlet Nexus and such and the occasional lewd game of course. I think AAA games will be best played off of Nvme SSD while most other games, you can get away with a MicroSD slot. I'd skip the eMMC $399 model unless all you do is play indies and AA games.
Anime: Haruhi Nsfw Anime Thread