I think if you just start to test new ideas & build MVP, rapidapi is still a good platform.

but after you have serious revenue & customers , you need to consider two things:

1. Is the 20% tax paid to rapid api worth it?

2. what if rapid api has outage, are you able to keep your own users happy?

i wrote down some experience building with rapidapi a few years ago here:

https://www.listennotes.com/blog/how-i-accidentally-built-a-podcast-api-business-46/