Mace smash attack does not trigger while descending with Elytra or during horse/donkey (or any other ridable mob) jumps. same thing with critical hits with ridable mobs.

Horses have higher jump strengths than players and that can be very handy when using a mace, although it doesn’t work when trying to land a smash attack on your way down just the way it does when not riding anything, aswell as the crit attacks do not happen when riding any ridable mob. also when descending with an elytra at enormous speeds and trying to land a smash attack with a mace it doesn’t work, it would be really cool to be able to smash any mob on the way down and save the players' health instead of breathing their last.