It's not as fast as regular DNS, 30ms is still very quick.
DHTs get a bad rap because of many recent DHTs that were horribly inefficient. But mainline is different. Many of the design decisions of mainline seem very limiting at first, but make a lot of sense for perf.
E.g. a pkarr record can only be 1000 bytes, so the entire message fits into a single non-fragmented UDP packet.
This is their example:
http://7fmjpcuuzf54hw18bsgi3zihzyh4awseeuq5tmojefaezjbd64cy/