Find a piece of leather a few inches by a few inches, and push a 2 blade through it. Now, pull on that leather in a few directions, mainly up and down and side to side. Watch how the slice moves. When you pull the leather the direction the slice runs end to end, the slice closes (the wound closes). Side to side, it opens. Now do the same with a 3 or 4 blade. You will notice, no matter what direction you pull that leather, at least one portion of that slice is going to open (wound remains open). It will never totally pull closed. The difference in a 3 or 4 blade hole compared to a 2 blade hole.
Let me proclaim ......not trying to kick a nest here ..... i love Zwickeys and Aces and Magnus and STOS and several others, I am not crapping on 2 blades necessarily. For animals I hunt, unless I may be out trying to get something done with certain tackle and set up, my go - to is going to be a 3 blade. Specifically, I am a big VPA 3 blade fan. Don't need replaceable blades. Anybody can sharpen a VPA 3 blade. You only really need 1 tool to do it ....... 12" mill bastard file. No fuss. Done. Kill a million animals with one head until you sharpen it so many times it's out of your weight requirements. Awesome bang for the buck.