This is mainly because the old "limit" functions were all restricted
to certain types, which is incredibly silly given how simple they are.
Macros are much simpler, and a warning gets raised if they're used
improperly with multiple types, anyway.
In the process, I also found and fixed a bug: it seems the original
author intended for escaping enemies to gradually accelerate to
fleeing speed, but the low value was indicated as the max value, and
the way limitFloat was written, that caused the max value to be used
(it was supposed to reduce the speed to a minimum of -15, but it
instead effectively assigned the speed to -15). It might be a good
idea to re-implement the old buggy behavior intentionally; depends
on whether the acceleration of jumping looks better or worse than
just immediately going to jump speed.