The documentation you're reading is out of date.
Once upon a time, when you looped for (1..1000), perl would create a list of one thousand elements in memory, and then loop over that list. Looping C-style (for ($x=1; $x<=1000; $x++)) would not have the initial overhead of creating the list, nor the overhead of holding that list in memory. For short loops, like your 1-10 example, this was a trivial difference.
In any case, this is no longer an issue. Perl no longer creates the throwaway list in memory; the two are basically equivalent now.
