I can use their NextJS Docker container anywhere though. Currently I do it on a Hetzner VPS for a few bucks a month and handle all the scale I need, no CDN or edge runtime required.
But they insist on put your NS on cloudflare as well and afair not accepting domains greater than 2nd level.
Coming back to the load - simple 3vCPU Linux based VPS on Hetzner could handle 4Gbit of traffic serving. Offloading your server fleet probably the last reason here. Geo presence - agree here.