Performance was always enough of a consideration that even BE's original implementation had both int32 and double types internally, though black-box unobservable (as in the black box, everything appears as a double).
As a side note, I'll bet you could have actually observed the difference via timing at the time, assuming you knew what hardware you were working on. On an early Pentium, a floating point add would have taken up to 3 times as long as an integer add (depending on implementation), so by comparing in a loop, you might be able to tell if a given value was being treated as an integer or a double.
