And even for a youtuber 4k 60fps is more than enough. How many people are watching youtube videos in 8k 60fps. How many people even have the internet speed for that let alone the monitor.
Not many but as Matt explains in his video, you can downsample the 8K footage to 4K to get higher detailed 4K. The same is often done with 4K to 1080p footage for the same reason.