I'll take ya one further: every single RPG character should be able to contribute meaningfully to every aspect of the game. In the terms of D&D and the "three pillars," that means that every character should be able to provide something when talking with NPCs, when exploring in the dungeon or the wilderness, and within a combat encounter.
A broader perspective: all RPG characters should be able to participate in all scenes. The alternative creates bad gameplay and usually results in players "checking out" during certain gameplay elements because they feel useless or as though they will hinder the party.
I swear this isn't a trap, but, in general, how do you think the mechanics of that would work?
Some (I'd say very few) systems account for this in an explicit way--2d20 encourages you to contribute to someone else's skill rolls, either with a similar skill or something totally different but complimentary in the situation (like rolling Command to help coordinate). Other games have more rigid teamwork-based mechanics. But what about in something like 5e?