There's a lot of room to fault how the disposable drone familiars work in 5e tooSometimes that just happens. Like, I'm playing a rogue in a game right now, and she's plenty stealthy. But the wizard's familiar can fly and also won't attract attention if seen in most circumstances, because it's just a bird. So when there's scouting to be done, we send in the familiar--but in a different party, I might be doing all the scouting.
I don't think it's a flaw of the game; it's just one of the quirks of how two features happen to overlap.