People who advocate for playing the benoni usually argue that they want whole board complexity with tactical opportunities without having to memorize concrete lines, where they can play conceptually... by comprison the QGD is drawish, the slav is more solid and it requires too much theory, and the KID... the KID is probably the closest alternative but it often leads to closed structures, and it isn't as conceptual you need to know the precise moves or you're just suffocated and screwed. Grunfeld lines there are very concrete and theoretical. In the benoni you play it conceptually for a win, which is what its proponents would argue.
I wouldn't argue that because, while you do avoid theory, I think you just give white a fantastic position that doesn't require theory from him either. I think for all those benefits you're just better off playing the benko. It takes a while to get the board to open up in the benoni, you have to be very patient. With the benko you have good initiative fairly early on and it lasts throughout the entire midgame.
The dutch could be an alternative, but it's unstable in a way that often comes back to bite black, it also requires alot more precision early on from black. Between the dutch and the benoni I probably would choose the benoni.
If I did have to play a benoni I would play the old benoni w/ an early g6, there are some interesting lines here and they're not often seen -
i believe benoni translates from hebrew meaning "that boy aint right"
if bobby hill played chess, hank would insist on a good ol fashioned ruy lopez for black and a queen's gambit declined, maybe a cambridge springs if he feeling bold. Then of course, bobby would dedicated himself to the benoni defense just because. Hit straight bobby!
THAT BOY AINT RIGHT!
oh and Benko gambit is straight BWAH! territory.