[taeric]

To be fair, it originates from a time when memory was tighter. Is discussed with some motivating text in Programming Pearls. I can't remember the context, but I think it was in a text editor. I can look it up, if folks want some of that context here.

[HarHarVeryFunny]

I did something similar back in the day to support block-move for an editor running on a memory constrained 8-bit micro (BBC Micro). It had to be done in-place since there was no guarantee you'd have enough spare memory to use a temporary buffer, and also more efficient to move each byte once rather than twice (in/out of temp buffer).

[osullivj]

Also useful for cache locality, a more recent trend. But I guess that's just another slighlty diff case of tight mem; this time in the cache rather than RAM generally.