Only if the measurements span several orders of magnitude and you want to keep the relative error low. Otherwise you'd be better off with fixed-point numbers, which are spread out more evenly (about half of the IEEE floats are less than 1 in magnitude).

And if you don't limit yourself to linear mappings, you can probably do even better with a non-uniform integer encoding.

Only on the human-readable level, which, when your brain is as big as mine is, doesn’t even like matter.