Using a clock in physics is not the best way to go, as the time factor represents a linear duration of time which in turn causes all kinds of problems.
Of course clocks have their place and things would be a mess without them, but when it comes to explaining and defining universe you got a tiger by the tail.
We use a clock to determine the speed of a bus and we use a clock to determine the speed of light, which doesn't seem to bother most people at all. It seems perfectly logical to them.
This seems a bit weird to say the least, because we make some huge assumptions concerning time.
We also make some huge assumptions concerning our ability to measure mass and energy on the basis of a linear relationship, without even blinking an eye.
I have to say it does seem a bit on the weird side.