Yeah of course one of your guys would ruin it, as every pokemon can be countered. And besides if I come in against a slower pokemon with the basic smeargle, switching to Primeape won't do jack. I'll sub while you switch. You'll come in and I'll belly drum after you break my sub. Salac Berry will activate and then I'll BP to Gyarados or whatever else I have. Then in that situation, I'd pretty much sweep your team.
All the Smeargles in this thread including mine are obviously not gonna be used for battles, this is just a fun exercise. But the Belly Passer is practical and it has good use and so is the ingrain passer in BP chains and in some cases an endeavor set. Pretty much any other Smeargle is for a laugh.
We haven't battled before and since I don't have a router at home and the school year's up, I can't battle you. I'd gladly take you on, on shoddy battle.