I don't have a strong opinion one way or the other, but maybe it would
be better to consider lujvo:
kelzu'e x1 plays x2 (activity) with plaything/toy/props x3;
z1=k1 z2 (z3=nu kelci) k2
Also, {pagbu} can be (and has been) used to mean "x1 participates/
takes part in x2", which can mean "plays" when x2 is a game.
Jorge