Well, Stadia is dead. To be fair, I'm surprised they even included such a tool in the first place, from Google I would've expected to just kinda let it die.
I still don't get why it would be time-dependent. If they are going to release a simple tool with a single simple function like that, why not just release a standalone tool that can be run in perpetuity? Does it really require authentication with Google servers or something to modify the firmware?