The smaller front arms might be for tripping prey, since this creature was designed after a cheetah. Cheetahs are known the trip their prey with their front paws. To have extra limbs to do it, rather than using legs made for running would certainly be beneficial to the species survival. Of coarse I maybe wrong. It could be to bring the prey closer within biting range, in which it's legs cannot, or that this is a female, and the arms are used to carry young. Perhaps, it maybe a male, using it's impressive arms to attract mate by fighting others. Who knows?
I am very impressed by the dynamics of this picture! Everything is spot on. And you have blended the off kilter balance of the cheetah pursuit with a sprinting greyhound, plus a huge helping of god awful monster! Really stellar concept work.