They want fast resolution of names that point to websites hosted by Cloudflare. Cloudflare makes their money selling their network to businesses that use it, and anything that makes that service better for the end-user increases customer stickiness.
Traffic from heavily censored regimes to its big customers, which often end up being censored due to user contributions, I suppose.
Making the internet fast and reliable, and arguably DNS resolution plays into that.
Could be a precursor to launching an OpenDNS competitor.
Is OpenDNS even as relevant as it was earlier, before Google DNS appeared (and then OpenDNS was bought by Cisco)?
Maybe not _as_ relevant, but still a considerable number of clients are configured to trust OpenDNS, and their far more ambiguous stance on what exactly this is for is appealing to some people. For example, OpenDNS says yes, absolutely it is their business what you're looking up, and maybe you are a Concerned Parent™ who wants to ensure their children don't access RedTube, so that feels like a good idea.
I was thinking more along the lines of their SME offering. DNS filtering is an important layer in network security and CloudFlare’s position of being in the middle of a large portion of Internet traffic, alongside now trying to attract a chunk of general DNS queries, potentially gives them a great deal of insight into who the bad actors are.