With two QBs that could both run the ball as well. A lot of play action in the backfield with two split QBs (on the field at the same time) but they could also hand it off to the other and there is a threat of run or pass from that one as well.

The saints have already done this to some extent with Taysom in the past few years.

It would be extreme tough to defend, especially for teams that never see anything like it.