@Daz:
Well, it gives the heroes an easy way of instantly destroying his weapon; lock blades, slide your saber down to the horisontal blade, and voila, you've now cut a diagonal slash through the hilt. destroyed the weapon, and propably ruined your opponents hand. All directly facilitated by the sabers design.
So from the heroes persective, very useful.
With a normal lightsaber that will also simply lop the guy's hand off. Granted those protrusions seemingly defeat the purpose of having a cross guard, but what if those are actually pipes, not emitters and they house a beam underneath? That way you only cut through the pipe but your lightsaber gets blocked by the guard saving the guy's hand in the process, which is the reason a countless of real life swords had those in the first place.
The idea of the crossguard is actually the very opposite of impractical, it's just that the execution seems suspect from the visuals alone.
And really, if people gave Maul's dumbass double sword a pass, a shoddy looking cross guard should be nothing. At least that beam crossguard won't kill me if I take a remotely wide swing with the saber. I mean, the cross guard is at least based on a real life practical thing that worked.