I do, but mostly Iif I cannot carry my FF stuff for whatever reason.
I do use 20 MP-models.
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
I have a 20Mp Pen-F. Love it. Great carry around and vacation camera. With prime lens it fits in a pocket. A full kit; body, UW, Std, TP, and one fast prime for low light fits in a bag smaller than my GF's purse. Never understood why mft isn't more popular?
I never used a 16mp so I don't have a reference, but besides IQ, I'm sure every feature has improved too. I keep thinking of picking up an EM-5 III.
I have a G9, an awesome camera. I sit on two boats, so I also have some Fuji stuff. I mainly use my G9 for macro - butterflies and and other insekts, sometimes video - slomo. (For everything else I never take video clips). I also use the G9 with the Oly 45f1.2 and Oly75f1.8 and Laowa 10f2.