The Mozilla web page on how it introduced an implementation of "DoH" in collaboration with Cloudfare is actually a fascinating read. And going through the comments, it seems that this approach in not without controversy.

The advantage of DoH preventing man-in-the-middle attacks enables it to circumvent deliberate firewall-level DNS filtering (corporate policy, adult sites, other filters). There is also a legitimate concern of such configuration being done at the browser level rather than the OS. However, at least DoH is available for anyone to try on Firefox (version 62 and later). Instructions are in the above link.