Multiboxing has proven time and time again to not be what most people think it is.
"You can't raid!" "<yogg_10man_heroic.mpeg>"
"I'm gonna pwn in PVP YO!" "Uh...ISBoxer is broken and I can't figure this crap out."
"I have 10 herbalists I'm so gonna make mad bank on all these mats." "https://duckduckgo.com/?q=what+is+supply+and+demand"

I can't count the number of times people have either gotten into it thinking it would make them gods among mortals, or told everyone that nobody can 5-man <insert hard dungeon or boss here> and been proven wrong. I suspect a lot more people multibox because you just never know what will work or won't until you try. If you're the explorer/tinkerer/etc. type, you'll probably like it. It's really hard to tell you which hobbies will keep your interest, especially when it's something as complex as multiboxing.