Tbf you wouldn't use/switch to jj for (because of) those kind of commands, and are quite the outlier in the grand list of reasons to use jj. However the option to use the revset language in that manner is a high-ranking reason to use jj in my opinion.

The most frequent "complex" command I use is to find commits in my name that are unsigned, and then sign them (this is owing to my workflow with agents that commit on my behalf but I'm not going to give agents my private key!)

    jj log -r 'mine() & ~signed()'

    # or if yolo mode...

    jj sign -r 'mine() & ~signed()'

I hadn't even spared a moment to consider the git equivalent but I would humbly expect it to be quite obtuse.