Alarm clocks, car clocks, coffee machines, and microwaves aren't either. What's your point?

I'm pretty well aware that our time-keeping methods are imperfect, but they would be even more inaccurate if we kept them the same on other planets. (Because, again, we measure time mostly by comparing the positions of objects. The universe does not bend itself in half just to fit our 24-hour day / night schedule.)