Turning it off in the browser is a PITA, even for just a home user. Family of 4 and if I wanted to turn it off I'd need to do it on 9 computers, 3 tablets, 4 phones and 2 set top boxes. Not saying we're exactly average... but the shit adds up fast. [edit: +1 computer, forgot one]
I am currently using both, and as someone at work, I am glad for DoH being built in on Firefox.