If it comes to iPads and Macs, paying $60 with the ability to access the game on different platforms + cloud saves may make it a compelling buy for the platform.
Now, if only Apple could beef up the AppleTV enough to be able to handle this game like a proper console (or at least close to it). It’d be an excellent experience given that controller support has arrived on all of these devices.
It’s not a new feature either. I used it at least 4 years ago. Plugged my phone into my monitor, Bluetooth controller, and I could play games on my nice monitor. It’s even easier now with USB-C I’d imagine, I was using the lightning-hdmi dongle.