Speaking for myself, i can say i use her more than alot of people on the puff boards, not speaking for DaPuffster of course, or Woodman. But i can say that alot of the MU's make it almost ridiculous to completely main her.
Link however may have the tools to fight off characters Jigglypuff can't. But jigglypuff can do better against the characters Link can work. With the exception of Snake, G&W, DK, squirtle and ..... I can't think of another one offhand, everything else is either advantage, even or slight disadvantage.
At least against link it's advantage. We have advantage on falcon, lucas, ganon, bowser, sheik, and go even with a decent number of characters.