I think Disney sorta forces
some people to do this because of the locks on the system which are in place for a reason. It's been this way since FP+ but to Dave's point what IMO he's saying is when you take a time slot from an attraction you have no intention of riding it prevents someone else from getting it. That is why you'll see at times people expressing shock that X attraction either is out or has return times later on in the day as there are some people strictly using that attraction to move along in their ability to book more.
All personal opinion I don't see a big issue when it's just a case of there's just not any other attractions you want to ride (or in some cases can ride) however when you're really just trying to maximize the number of rides you get in that's when it gets dicey. I do think most of us understand Disney puts in place the restrictions for a reason but it does have the effect of potentially penalizing other guests who want certain attractions that people are just simply using and not intending to ride just to get more rides in.
There's enough attractions that I know my husband and I can ride or shows to do (DHS isn't really where we go to watch shows which is the park the OP is asking about) and so personally we never used attractions as a means to get more when we booked FP+ (we haven't used
Genie+ nor LL yet) but it is a common enough way of doing things that people talk about on the Boards. IMO if you're going to do it pick the attractions that have the least affect overall (which is what the OP is asking about in a roundabout way).