Ooh, if they can switch direction to come out the other sides that could be so USEFUL.

Ummm. If I had to guess: in between the two images we see, Ethan released the dagger hilt momentarily and reversed his grip, catching it in a forwards-facing position for the next blow. OR. In a completely un-substantiated theory… all these bladed weapons can have the ‘light blade’ emerge from either direction depending upon the will of the exorcist.
Do we have 100% proof that blades (like swords or daggers) can only come out of one of the two short ends of the hilt?
I know in an actual sword, there are numerous reasons this would not work… from the shaping of the grip to best fit the shape of your hand, to the cross-guard needing to cover the fingers and protect the wielder and help balance the weight of the blade, etc. However, beyond being an artifact capable of channeling the gifts of the exorcist, do we actually know how practical these ‘magic’ hilts are? I do not know if Asmo has ever specified.