API incurs very different usage patterns than humans do, That affects margins and professional plan was made years ago with human use in mind, not programatic access. Paying for only what you use for API is the most fair way to do it.
I think it would be nice to have a small monthly API allowance in the professional plan.
Absolutely, even for personal use sometimes you need API access like letting a local model access the internet or even a small python script to search and filter related research papers to your thesis. Limiting all API access behind another paywall is dirty.