While recovering data I see a warning related to recovery to the same drive. Why it is not recommended?

This can result in data on this or other (deleted) files being corrupted!!! Why do you need to undelete to the same drive the file was deleted from? Is this is your only drive? We try to discourage recovering to the same drive, although it is permitted. This can result in data on this or other (deleted) files being corrupted!!! (See, we said it twice. We must really mean it. Of course when you only have one drive, you are stuck between a rock and a hard spot)