To properly handle secret scanning requires calling live APIs to test if keys are "real". And you need to have a way to file tickets when you do have findings... if you rotate a cred from production, that's now an outage, so you need to coordinate multiple teams.

It's a lot of work and free tools only solve one part of this. I can't speak to any of the vendors in this space but I can attest that it's a harder problem than it seems!