Sorcerer only has a few spell slots. Barbarian has infinite punch slots.

TWO punch man!

Some people enjoy the simple pleasures in life, and more of a good thing is an even better thing.

Fiend Bladelock getting all the sword of Paladin with all the fun of Sorcerer. Sure, they only get 2 Fireballs per Short Rest, 6 per Long Rest if your DM does SRs as intended, until level 11 when Warlocks get more slots. But, when they run out, they can hit twice.