[DenseComet]

Cloudflare sells the domain at cost. I think the idea is that its an extra service meant for their customers, not a service for the general public. As they are a DNS provider, their customers will use cloudflare nameservers. If they didn't, they would no longer be customers.

[cirno]

That does make sense. If I were using Cloudflare I suppose it would be a no-brainer, and if I were Cloudflare and didn't want people not routing their traffic through me on my registrar, that would be an excellent way to discourage it. If they're forced to offer to everyone as part of being a registrar, then the combination of all of the above is my answer. Thanks!