[formerly_proven]

There’s a trade off between sharpness and noise, the GFX have an intentionally lowered fill factor to, essentially, produce a sharper image. Meanwhile noise is one of the most important things when marketing mainstream cameras (next to AF), so they go for gapless microlenses etc.

The reason this impacts sharpness is because a lower FF gets you closer to Shannon’s ideal point sample, while a 99% FF is like a pitch-sized box filter.

[account42]

There is also a tradeoff between sharpness and aliasing, that's a bigger driver for microlenses than just capturing more photons. A point sample is only ideal if your sample resolution is above the nyquist frequency which for the real world it won't be.

[formerly_proven]

Yes, this was nicely highlighted by the GFX50 vs. GFX100. Both are around 50% fill factor and have no OLPF, the GFX50 produces a lot of aliasing artifacts, the GFX100 much less so, because Nyquist moves up some 40%, so diffraction takes more readily care of attenuating these higher spatial frequencies.