So the bigger question then is what happens when they change this? Or go away. Also, have you seen what "Additionally, different hard limits apply for each plan." means on their pricing page[1]? Domain limits, maximum files, etc? What those might mean when you scale beyond expectation?

I don't mean to discourage. But big vendors pull the rug out from under people all the time, sometimes ruining a business because there's no viable alternative.

Make sure your eggs can be put in different baskets if need be.

[1] https://vercel.com/docs/v2/platform/limits