I thought I would try it and I thought there was a reason. why no one used it so I battled a a stockpilein Pokemon. and it took a quarter of smeargle health. in it stockpiled 3 and I guard split. when it stockpiled 3 so my question is. is there a reason why there is no strategy for it.
I'm going to answer mainly for the purpose of taking this off the unanswered list. From my experience as a stall user, a big perk to having good defenses is the ability to switch into attacks and not take a lot of damage. Obviously Smeargle can't do that, no matter which moves it knows.