"War by the rules"

I don't understand what's so good about Gnomes here? Or am I missing something? And why are Mages rarely left alive?

Gnomes are good in many ways, but it's difficult to play with them on a large map due to the low percentage of luck... in general, I think that this is exactly the reason why they are often left behind, and as for the fact that Mages are "rarely left alive";) I think they are simply quickly eliminated by both opponents; it's a tricky race.