I have but only to cache data used by cron/bg jobs. We still had Redis for an actual platform system cache. The thing is that Redis cache was created and managed by some framework middleware so it did not seem right to invoke it in code/scripts that bypassed that middleware.

It was ok. Never really failed and didn't affect the user-initiated CRUD ops though ofc the bg jobs ran when the users slept. Still wouldn't bet my life on it.