I give you now outward point of view. If yuo robot is so bad that it can win because other robot have better batteries perhaps you should build better robot? If safety of this lithium cell is not a problem then it should be ok?

In end batterys are only small part of robot and that it win or not. My robot was only robot with lipo battery in 12kg em compatition. dit it win picause better batteries? - no it lose because I am bad driver!

But 270g 3S 3200mah lipo VS 650g 10cell a GP3300 and lipo is at lower price! I love Finland 3