In this case, you're moving the trust you put in your ISP or anyone who resolves your DNS queries to Cloudflare. Depending on where you are in the world, or how your threat profile looks, this might be good or bad, or degrees of good/bad.

That everyone is starting to tunnel more and more of their traffic to one single entity (Cloudflare or not) is overall not that good. But certainly not 100% bad.