it's just the appleTV+ streaming service, not the appleTV "box" so no apps or games.
it does work almost the same as the one on the appleTV. The one exception is on the appleTV, it will also pull information from several of the other streaming apps on your aTV. Like Amazon Prime or Disney+, if you're working your way though a show, the next episode will appear in the up next section in the appleTV app on your appleTV , but not the app on your TV. When you select something to watch on the appleTV, it will open the appropriate app and start playing the show in that app.
Also because the app on the aTV ties into all the other apps, it can search them as well,
One notable exception to this is Netflix, it only shows in the Netflix app.
With the app on your Television, and with a subscription you'll be able to watch apple's exclusive shows and movies, like ted lasso or greyhound,
There are also premium add on channels like HBO and CBS, if you subscribe through appleTV app those will also be available. if you've subscribed directly to those services, or have access through your cable company, you won't be able to access them inside the aTV app on your TV.
Direct or through cable company subscriptions will apple in the aTV app on the appleTV, so there's a very good chance the up next section in the aTV app will look very different between the TV and appleTV.