The bundle does give you a Chromecast Ultra and Stadia controller to keep, but you’re getting the same three-month trial of Stadia Pro that any Premiere Edition buyer gets. You’ll have to keep subscribing at $10 per month if you want Pro features beyond that, or else resign yourself to using the free 1080p tier when it’s ready. You also have to use the promo code for Stadia within 60 days of receiving it, so you can’t sit on the deal until there are enough games to make you happy.
This does stack on top of the Disney+ one-year deal, mind you, and you can always cancel before the Stadia Pro trial is over. Think of it as a way to flex your internet connection’s muscle and wind up with a couple of goodies when all is said and done.