Besides the tread patterns, I think there is also an important reason why we prefer DH-style tires on MUnis: they are wide. DH are the widest tires (if we rule out those fat tires first), and MUnis crave for wide tires much stronger than MTBs.
I’ve done a fair amount of xc style muni with a slick tire, and can definitely say there’s a reason somebody invented knobs. The most important thing to think of when reading a tread pattern is how the treads/knobbies connect to the ground. Roll your tire in the snow or mud and look at the pattern. If the treads tend to point forwards then they will help with forwards acceleration, whereas if they point backwards they will help with backwards/negative acceleration or, in simple terms, slowing down. I have noticed most tires seem to have more of a slowing down tread design, probably because it’s safer in that if you can reach a speed without tread optimized for reaching that speed the treads should be more than capable to slow you down again. There’s also knob positioning, such as how far over the edge/approaching the sidewall they go, which can determine cornering ability. My rule of thumb is to use whatever I have on hand/installed already, but if I’m choosing a new tire I’ll look for something as gnarly as the terrain I’m going to use it on.