I have wiggle on my list for this morning, but I don’t know if I can show a very useful case for it.
I understand from the program description that wiggle is designed to patch code where patch itself can’t, because of conflicting changes or some other error.
Personally I couldn’t come up with something so intricate to show what patch couldn’t do, but wiggle could. It’s another one of those situations where I’m trying to find a broken case for a program, so I can demonstrate another program. 
Which isn’t very easy if you’re not one of the people who immediately sees the use of wiggle anyway. I’m guessing if you read through the description of wiggle and say to yourself, “Hmm, that could be useful to me. …” then you’re already way ahead of me.
So I’ll leave it at that. I should mention that wiggle is in Debian and AUR; both wiggle and wiggle-git stopped on warnings for me, so you might want to disable warnings that are treated as errors when you build it.
Of course, the Debian version runs fine. There’s the convenience of a precompiled distro. Then again, the Debian package page links to a dead home page, so there’s the convenience of AUR, too. … 😉
Inconsolation 
That could be very handy in situations like suckless.org software 😀
I came here to say exactly what Theodore said: adding multiple feature patches to something like dwm before compiling it sounds like just the job for wiggle. I’ll come back and let you know when I grow the stones (and make the time) to seriously dive into dwm.