OK for timekeeping but I'd say that's mostly for human scale stuff and as you say involves dumb stuff like leap seconds every handful of years, and presumably the Earth's spin and orbits will change more radically eventually - i guess we're just expecting humans to die out before it becomes too much more of a problem.

But thinking about measuring for science - irrespective of human geocentrism?

Should scientific measures all be built up from planck units or something?