Most of the numeric quantities used in games (aside from integers for counting or indexing objects) are single-precision floating point. This is IEEE format, which allows for numbers as big as 1e38 and as small as 1e-38.
Such a large dynamic range makes sense in the context in which the IEEE floating-point standard was defined: roughly speaking, for scientists, who routinely deal with very large and very small numbers.
Intuitively, games seem unlikely to have to deal with such a wide range. Say you measure distance in meters. Draw distance maybe a few kilometers? Smallest objects a few millimeters? Granted that multiplying numbers can temporarily take them out of the original range, it would seem sufficient to have a dynamic range like 1e8 to 1e-6, whereupon more of the bits could've been used for greater precision.
But maybe I am missing something about the data and calculations routinely used in games.
What sort of dynamic range do games actually use?