Many people, who play 4K Stadia games with a Stadia Pro subscription, maybe playing 4K games for the first time on a 4K TV or 4K monitor because their computer may not be good enough to play a 4K game installed on their computer's storage drive. Stadia 4K streaming with their faster broadband ISP maybe the only affordable option they have to play a 4K game by streaming the game in 4K to their settop box, 4K smart tv, or PC with a 4K monitor. Stadia Pro 4K maybe the first 4K game streaming service which they use to stream their game in 4K, so they can play 4K games on their TV.
I read on Google Stadia requires 35Mbps internet for 4K 60FPS that users would need a 35mbps connection for 4K 60 frame per second Stadia game streaming. Most 802.11N routers have speeds of 150 megabits per second or faster, so they maybe able to use their average 802.11N router Wifi to stream a 4K game if they choose not to use wired 100mbps or gigabit Ethernet to stream games in 4K.