I use Vercel (and Netlify) and once you spend the 2 minutes setting it up you never think much of it again as it just does its job.
Granted, the Vercel edge network is amazing, but Google routes internal requests way way faster than the edge can communicate with Google's infra.
Vercel is great for things that aren't stateful and for automagic build configuration and asset serving. But not great for anything needing a DB.
the primary decision driver here is hype factor
it’s just more fashionable to use Vercel than AWS
much of web development today is like this
On our team, we deploy our web app through Vercel primarily because of this (maybe there is some hype factor bias in there too?..). Everything else we rely on runs on AWS. We don't necessarily need Vercel for any of the edge computing or serverless environments, but the experience of building, previewing, and deploying our app is FAR superior to AWS's Amplify offering because it just works.
Trialing Amplify for a few weeks led to a world of hurt, leftover build artifacts in our accounts, failed builds left and right, unreliable preview environments, etc.