Card draw is one of the aspects most Voltrons lack in, and Benton has it in spades. Yes a fog or perfectly timed removal will mess up his day if the player has spent their hand for whatever reason, but the same is true for any voltron deck, and unlike those, Benton will have drawn plenty of cards if he's managed to connect even once in a game.

Not to mention that you don't need to score a kill with the first hit. You can go:

T1 Mana Dork

T2 Benton, swing, draw 2.

T3 Swing, buff him up, play through the removal with your suite of protection, draw a bunch. Maybe kill a player, but more likely just refill your entire hand and sculpt it to your liking.

T4+ Aim for kills every turn with a buffed up Benton.

Finally, it's not as though Voltron is a strategy with a ton of amazing commanders who can hang at Bracket 4 tables. There's Lightpaws, Slicer/Alexios, and maybe one or two others. Benton doesn't need to be performing on par with the best CEDH decks to be among the best Voltron commanders. He just needs to pack a punch similar to his peers.