I think you're using "gimp" unfairly here. This isn't about purposely choosing not to use advantages that everyone has, or that have no cost, simply to increase difficulty.
This is about choosing explicitly how to develop your character, especially in early-game when perks are precious. You're looking at it from the standpoint of a lvl 40+ character who can have BOTH Gunslinger and Rifleman maxed. How about if you're level five and you've just found that snub .44 near that unmarked water pump thing to the east of Sanctuary? That is when these decisions matter because you can then decide whether or not to make this weapon a significant part of your game, spending the perks to support it as you grow your character or not. OTOH, if you found a hunting rifle earlier and have already moved in that direction, you might decide to ignore the .44.
This is (nominally) a role-playing game and the weapons are balanced to provide role-playing choices that are still viable for playing the game.