It's specifically CloudFront Functions and not something like Lambda nor Lambda@Edge, so cold start shouldn't be a notable issue but you're far more limited in

It's specifically CloudFront Functions and not something like Lambda nor Lambda@Edge, so cold start shouldn't be a notable issue but you're far more limited in what you can do with them. I think this is more suited for simpler use cases if you truly want to stay within the boundaries of the free plan.