Right now is a transition phase, it is absolutely intended that some other mechanism becomes available in the future which is more resilient. The canary domain provides a clear pathway though for existing Do53 configurations to prevent DoH when necessary.
There's still some specific cases where DoH is problematic, but these are being eliminated over time as the technology matures. As an example of this, split horizon DNS in corporate environments is a good choice. Right now, the only realistic way to provide this is with Do53, so DoH must be disabled, but with Microsoft adding DoH support into the Windows 10 DNS Client, they are likely soon going to also support it on Windows DNS Server, which would enable businesses to make use of DoH internally and to simply set the endpoint by enterprise policies.
DoH is a few different things, but at it's most basic it's transport security for DNS, which is a fundamentally good idea any way you slice it. At some point in the future, plaintext DNS will effectively cease to exist and that's a /good thing/. There are several different implementations of encrypted DNS in the wild besides DoH (DoT and DNScrypt as examples), whichever you choose, any option that encrypts DNS both on your local network and across external networks improves privacy and security.
It takes a pretty long time to transition fundamental protocols like this, but a future where more things are sent across encrypted transports is a good future. Plaintext DNS is incredibly vulnerable, and it's also in an area which isn't heavily visible to most users, which is not a recipe for success.