The DNS resolution is done by the exit node. Once you go to foo1.com or foo2.com after the resolution you are still going to separate IPs and subject to the same benefits. There's really nothing to compare this CloudFlare service to except just like an HTTP API as an onion service (or bind or whatever).

There is safety in numbers accessing the CloudFlare service. It helps reduce traffic analysis attacks that could otherwise occur on exit nodes and the exit node's possible-non-authoritative resolver. Because correlation between the circuit to CloudFlare's resolution and the exit node's site access is a bit harder. Granted once you enter the HTTP world and ask that second level domain to start the TLS handshake, they can see where you're going anyways so it might not matter. But it can prevent you from being poisoned by the exit node's DNS resolver. It just removes one layer of trust away from the exit node.