I'm in the skimmer camp. Those that run skimmerless either have an alternate route to nutrient removal (turf scrubber, refugium), run a more natural system and keep corals that are fine with higher nutrients, or keep a lower bioload.
To me it's like driving without power steering. Can you drive the car without power steering? Yes. Do you want to? Me, preferably not. Why not take the extra assistance with nutrient removal if it's right there and you can afford it?
I'm not saying keeping a thriving, gorgeous tank full of high end corals and tons of fish isn't possible without a skimmer, but the odds are less in your favor without one in my opinion.