They both easily let you to make a mess of polygons ans edges if your are not careful or just accidentally. Double coinciding edges , double or even triple coinciding faces sharing same vertexes. I once saw a whole second layer of faces laying on same vertexes. Blender has a few "selection by traits" option to select and…
I want to merge the selected vertex with the one above it. But when I do, it seems like it merged properly, but it really didn't. The result geometry is a mess. Those two edges are not real edges - I can't bevel them, they're not part of a loop, they break multi-cut and so on. I really don't understand how Maya works.