It seems only natural for gaming to gravitate to the cloud. People don't like the idea of it for a few reasons and are rightly wary of possible ownership, cost and performance issues. However, I think it's the way forward and will change the gaming landscape forever. The majority of people would rather not spend hundreds on keeping a PC suitably spec'd to run the latest games year on year. Consoles offer better bang per buck but still have an upfront high cost with games that are now £45 a pop.
People want the flexibility to use different devices to fit their life style and they don't want to have to jump through hopes to share gaming footage and do the things we are currently doing. Stadia offers a lot of solutions and seamless integration. Imagine not having to worry about upgrading local hardware, knowing that you will always have a consistent rich experience that devs originally planned with nothing left out. It's very appealing to people like me who don't have much time on their hands and just want to switch on and play for quick fixes. It's so accessible, so fast. That's the idea. I can't justify dropping £400 on a gfx card to play the latest AAA game a couple of times a month, but I'd still like to play them sometimes given the chance.
I welcome the change and potential shift and I think it will be interesting to see how it pans out. People knocking it before it's even been implemented I think are concerned about their investment into their own "stuff". You need to consider breaking away from ownership mentality and see gaming as a fast moving thing that one consumes like a service. Gaming goes hand in hand with subscription models and was always going to go down this path eventually. I share the same concerns with Google holding a monopoly though and hope costing is kept controllable and affordable with minimal advertising. Performance issues and latency will indeed make or break it but I can't see them investing this much into it without them having ran real world large scale tests that have worked.