It's "netflix for games". I am baffled that anyone would "purchase" anything on a streaming platform.
As it was released, I had zero interest in Stadia for all the reasons mentioned elsewhere in this thread. And I am the perfect target consumer for Stadia. I have a large monthly budget for games, I travel enough that it makes sense to have a portable gaming platform, and I embrace tech early. Even with all this, I had zero interest in Stadia simply because it was a Google product that I knew would be canceled.