Well, let's say I have a bunch of roomies and probably they will use the TV too but I'm not sure how it works, I mean, what would be available for them? Contacts? Youtube Search? Main concern would be if they could access to my Google Photos gallery or how difficult it could be?
Tried researchin a little bit in other threats but found something about Google Photos being disable but nothing about it still disable.
If you are concerned about privacy create a new gmail account for use with Android TV.
Keep in mind that means that apps you purchase in the play store would be tied to that Gmail account.
It all depends on which apps you put on it. If you have YouTube on it and you are logged in, then they could see all of your history. I believe you can log out and they can watch as a guest. Your Google contacts aren't able to be seen.
Like I said, it is all about which apps you have installed. That is all they will be able to see. There is no official Google Photos app anymore, but there are 3rd party apps that will display photos from your Google Photos account. If you don't install one of those apps, there is no way for them to get to your photos.
The only way they can access your Google Photos library is with Google assistant using their voice, which has the option turned-on by default in the assistant settings of your phone, just turn it off, so the only things they will get access with your account are YouTube, Google Play Movies, Google Play Music and Google Play Games.
Plus photos doesn't work on Android TV anymore unless you sideload.
Make an account just for TV/your house, and then link them with family sharing so that you can still use purchased items (apps, movies, etc) between the two google accounts.
You should be able to use a restricted profile to limit access.