Having three decimals confuses people in case of integer value: it is rather easy to confuse 3.000 ms with 3 000 ms. We cannot set decimals to 0 since it would round any non-integer values, but we can change decimal value to 2 or 4: it is harder to confuse 3.00 ms with 3 00 ms or 3.0000 ms with 3 0000 ms since such format is not widely used for big integers.
Having three decimals confuses people in case of integer value: it is rather easy to confuse
3.000 mswith3 000 ms. We cannot set decimals to 0 since it would round any non-integer values, but we can change decimal value to 2 or 4: it is harder to confuse3.00 mswith3 00 msor3.0000 mswith3 0000 mssince such format is not widely used for big integers.