The performance of setting currentTime on animation components really depends on the number of bones and the number of animated characters in a scene. Internally the function setCurrentTime on pc.Skeleton is called which you can see here https://github.com/playcanvas/engine/blob/master/src/anim/skeleton.js#L216.
Setting the currentTime of an animation has been used in some projects e.g. to synchronize audio and animation like this http://playcanv.as/p/klyMJ4h8 .
So I suggest trying it out in your project and see if it works out well for you