You meant this one
https://smile.amazon.com/21-INC-21BC1-Bitcoin-Computer/dp/B014RD021C?
With it's specification (0.9 GHz ARMv7 with 1GB SDRAM), this device won't able to run windows (as standalone device) due at all. I doubt it can even run full nodes without struggling.
I'd really like to get my 21 bitcoin computer running to see how profitable it may be.
Profitable? This device is aimed for Bitcoin developer, not miners. I'm sure this device is useless for mining.
So, why it is made and how is this thing work? Is it like a wallet or is it a computer which has 21 bitcoin inside?
How about you read read the link i mentioned?
TLDR :
1. It's made for developer, the one who create/develop Bitcoin protocol, wallet, payment processor, etc.
2. It works just like any computer (when used as standalone device)
3. You can use it as wallet and computer, but it doesn't have 21 bitcoin (obviously)
But as review on amazon says, it's overrated/overpriced device. Next time, DYOR and ask others before buy something you don't really know.