Excellent question, I suppose you could call Cloudflare decentralized in some manners, it depends on what you want to do. For a fully legit application, sure no problem. But if there's any risk to get shutdown it's not really the solution you're looking for.
My personal approach is to use both Cloudflare and no Cloudflare. Let me elaborate. I have some servers, let's call them A, B and C. Each has it's own domain i.e: A.example.org, B.example.org and C.example.org, they all has their own valid ssl certificates so not depending on Cloudflare. Then on top of this I added a Cloudflare domain which is basically example.com (note the difference .com and .org).
So what do I get from this approach? well the only drawback I can think of is that I don't get Cloudflares fancy DDoS protection, but I get mirrors, a decentralized cluster and a smart loadbalancer powered by Cloudflare for the average Joe who think mirrors and decentralization is something evil because that's what he's being told 🙂