Should I let my roommate use my switch console whenever he feels like it?
Why won't you let him use it? It seems harmless enough.
Whenever I come and go and even sleep, I see that my roommate is playing with switch consoles. I don't want him using it.
It's your Switch and you have the right to keep it to yourself. Your roommate should buy his own.
My roommate shouldn't have it. He's addicted to it. I know that he doesn't care about anything else.
If he is addicted to video games and is always using your switch, then you should want to take it back so that you can help him with the addiction while getting back your own stuff. His playing on your switch is very problematic, and you might want to hide the switch after you get it back in the future.