[MrFlippant]

Yep, it's all about resolution, both on the XY (pixels) and on the Z (layers). You can go pretty thin with layers on a filament printer, but that also introduces new things to deal with that thicker layers don't have. Resin, by nature, can do much thinner layers. The "rough" layer thickness of a resin printer is about the same as the "fine" layer thickness of a filament printer, but the resin can go considerably thinner. Also, the nature of the process means that there is a natural "dithering" of the pixels, which smooths things out even more.

They each have their place in the hobby, and they each have pros and cons to consider when trying to decide between the two kinds for a first printer. There's more to a decision than just resolution.