So does the axe, there is just one! Have you noticed that when you throw a runic axe it leaves a rune mark in the area of impact? That could also act as an AoE. It almost feels like they forgot to give him wave clear, Kelvin even gets his right click just for aoe wave smashing. A lot of people are turned off by boldurs awful early game and horrible laning since hes basically smacking one minion at a time with slow attacks, making assists and kills difficult, especially since melee come under fire at the same time. So throwing his axe in to damage more than 1 minion just makes sense to score some assists for when its too hot to just dive in and punch minions.
If only he had a 10th level Fist helix to really seal the build but its only 18% damage currently, doesnt say how low his HP has to be. Fist is slower anyways but its still good 1v1 if you pin someone, easily crits 200+
So basically the axe creating a damage effect around it while it sits there (or spins where it lands?) just makes him more interesting and gives him a less punishing early game, which might open him up to more people. His skills are really basic compared to other brawlers and would be a good counter-pick over Crash Helmet for a beginning helix, offense over defense