It's too bad the price vs performance ratio is absolutely atrocious. It's just not powerful enough to make sense unless you really really want a system that size and shape.
Considering the performance, limited RAM, storage and VRAM AND the fact that it does not run Windows (this used to make systems cost less), I don't think the 512GB model would be even remotely appealing for anything more than $400.
At this point you could buy a used 5 year old gaming PC from some local marketplace for half the price of a Steam Machine and probably end up with much better performance if it had a 3060 Ti or something similar. If the small cube form factor and having SteamOS out of the box are worth $500-$600 to you then that's fine, but for me it isn't even remotely close.
If you wanted to go 100% new, you could easily build a little ITX system that is significantly faster than this for the same money. Or, get something comparable that is half the price. Just last week I picked up a brand new, sealed Arc A750 8GB for $139, and that is anywhere from slightly slower to significantly faster than the Steam Machine's GPU depending on the game. It's not hard to find a Ryzen 5 5500 and an ITX AM4 board in the sub-$150 range. Add in 16GB of DDR4, 512GB SSD, ITX case and PSU and you've got similar capabilities for a little over half the price. Even if you bump the GPU budget up to $200-$300 it would still be nowhere near the $1050 of the Steam Machine.
It's a system I want to like because I think Valve does a nice job overall (especially with repairability of their hardware) but the price is just so bad I don't see it being successful. The Steam Deck was appealing because of its price point in combination with the form factor. The relatively inept RX 460 to GTX 1050 level of GPU performance was tolerable for a sub-$400 handheld. This... just doesn't make any sense.
Now for some blitting from the back buffer.