If you can choose both, and assuming these aren't tags but a separate system, then that kind of incentivizes everybody to choose both to increase the number of search results their game turns up in, but itch's culture isn't quite that mercenary, so let's just set that aside.
Choosing both definitely makes it less objectionable, but it also seems like it would make it less useful. I just don't foresee a system like that pruning too many results unless you search for games that exclusively use one tag.