I worry that bicarb+vinegar may have become a cultural phenomenon because it looks and sounds satisfying, not because of actual measured and compared effectiveness.

You want that in a drain though: the chemical reaction causes a great deal of foaming and agitation, which clears shit off the inside of the pipe.

Is it more effective than pouring hot water down the drain? I thought the foaming and agitation was quite gentle.

The PH you end up with also retards fruit flies and other nasties.

If you're not controlling the mix then everyone will end up with a different PH. Some neutral-ish,, some acidic (bad), some alkaline (and possibly only minorly so, the NaHCO3 might create a buffer, not sure).