What role does the Hagar have in Duel?

Nevertheless I find it annoying as hell if someone spams me with the primary - I can't hit him then.

this ↑ :-D

I reckon it should have some sort of cool down mechanism to prevent it from becoming some sort of machine gun!

I don't think so - it's pretty much inaccurate at anything further than close range (vs the machine gun which is quite accurate even across the whole map).

Useful or not - I like this gun, cause it's just a lot of fun to use it :-). (for all the more serious uses I recall something called Xonotic Pro Mode, where you can tweak the hell out of all the weapons - I don't care ;-) )