Price? How much is a Chromecast Pro? 30-50€? I think the app itself will be free on phones, PCs, etc.. The controller maybe 50€. Games as usual or maybe some form of subscription as an option.
There is no information on the subscription, to me it sounded more like you are renting cycles or a Virtual Desktop or stripped virtual desktop.
If I were to guess, you are buying games at maybe a reduced amount, but than you pay Google for running on their hardware. (just guessing, horrible presentation as to how this works)
Sounds like a GeForce competitor at this point.