That’s almost all of the time in my opinion. Expensive bar chocolate, to me, is the purview of candy lovers, not bakers. For bakers, chocolate is frequently just one component among many in a recipe, one that needs to be balanced against all the others. A sterling “grand cru” chocolate will be a hopeless distraction atop a doughnut, for example, and the doughnut will only undermine the qualities of the expensive chocolate. Sort of like washing a mouthful tandoori chicken down with a big gulp of Henri Jayer Richebourg — everybody loses.
A cheap chocolate — in fact the cheapest possible “chocolate flavored coating” — is what you want to blanket things like doughnuts and cookies. I might use something slightly better for dipping, say, the top an éclair, but then again maybe not. Cheap chocolate not only delivers a subtle chocolate flavor and texture that blends in well with baked (or fried) things, it also won’t give you those ugly gray-white streaks when it firms again. Nope, there’s no shame in the cheap stuff when it comes to baking. In fact it frequently makes baked goods better.