I guess Booker gives them the elite playoff scoring they need and he's very versatile as a scorer too as he can get to the rim and ft line, has the iso midrange game, and he can also play that off the ball and C&S role, as he's good at using cross screens and pin downs to find open space.
A Rockets lineup of Sengun, Jabari Smith Jr, Amen, Booker, and FVV could potentially give OKC a scare in the west