Need to make chocolate flavor swiss meringue buttercream and wondering can I add melted chocolate bark? I use it for cake pops and wondering if there will be any issue using it in the buttercream?

Look up Woodland Bakery with Gretchen Price.  She used Chocolate bark like this in some of her recipes.

But for the cost of a couple of bucks you can also buy a good quality chocolate candy bar at the grocery store, melt it and add it to the icing. 

AYou can use chocolate bark, but I'm with MB, the good stuff is so good, I only use Belgian chocolate in my SMBC, it's amazing.