Obviously Neckbeardy McNeckbeard sitting at a sofa knows more than all those generations of stupid, dumb idiot knights, men-at-arms and other soldiers who were so stupid they used swords....

seriously. The mace (or other short hafted weapons) is seen in certain contexts - maces are often symbols of authority (and still are to this day - pic related), carried by those in command, rather than those in the middle of the fight.
The related short hafted weapons, warhammers and the imaginatively-titled horesemen's axes are most commonly used on horseback, where you want something a bit shorter and more suited to quick beatings down onto someone below you, when you're in a press. Part of their use in those sort of contexts is probably because in a saddle you cant shift your feet, to generate power by torqueing your hips with a stepping strike. all the force had to come from the shoulder. In that sort of use, a weapon that concentrates the force, which is better suited to very close-range strikes of someone below you is far more effective.

but the idea that they're better than swords, or polearms, really is just daft. the simple fact of archaeology and depiction in art demonstrates that they are outnumbered 10 to 1 at least. Its obvious that they are not the best choice of weapon -

- because if they were people would've used them all the time.