Setting up a VPS with Node takes ten minutes and is miles cheaper. And it's not like you never have to debug issues with serverless configurations, which can even occasionally be harder to debug because of their proprietary natures.
Because you literally connect to a git repo and your site is deployed, and scales with load. Compared to managing a VM, system and application packages, config, backups and then how do you scale that?
I have what is basically a demo running on Vercel free tier, there's no way I'm maintaining a VM for that lol.
If I had a serious site, same. If I had a team, then the equation would be different.
It's like if Dropbox was an rsync server (no app) and it cost $10,000 a month for 1TB of space. Think it would still take off?
https://www.explainxkcd.com/wiki/index.php/2501:_Average_Fam...
Even with my own server, I've explored the option(s) just to avoid potential pain down the road regarding excess load.