I've never used Vercel, but skimming their site I think it's roughly the same concept as Cloudflare Pages / Functions.

SvelteKit has adapters [1] for both Cloudflare and Vercel (and Netlify), so they must be reasonably similar. I think Vite is a similar idea. I've never used it either, but have seen some references to Cloudflare deployment via a plugin.

The basic concept is really compelling IMO.

1. https://kit.svelte.dev/docs/adapters#supported-environments