I can agree with you if I put myself in a "min/max" mindset, where you're trying to get the best possible option in every situation - but in a roleplay sense, a tabletop sense, a story sense - it's far more interesting if more than one character engages in conversation with the world around them.

Having played loads of tabletop, emergent narrative often pits characters against challenges they're not well-equipped for - which drives the story in interesting directions. The Barb might have a higher chance of failure in persuasion checks, but does that really matter? I guess it comes to the higher level question of whether you'd reload a save if you failed a speech check - if so, I'd argue that it doesn't matter who talks if the player is just gonna reroll (as low rolls occasionally plague even the most erudite).

I'm happy for mods to have a fix for the "No one talks but me" crowd, but my thoughts are that Larian has thrown in so many contextual responsiveness for each character/race/class that it's honestly going to be interesting to see how different characters lead a conversation.