I think the other people got a little too technical.
The reasons are things like, if you want to play in time with a previously recorded track, or if you are using digital effects and need to be able to hear their effect on your instrument as you play it.
Both of these are less of an issue today than they were 15 years ago where a USB 2.0 audio interface added significant delay into audio and made it harder to get what you wanted out of the system.
The reasons are things like, if you want to play in time with a previously recorded track, or if you are using digital effects and need to be able to hear their effect on your instrument as you play it.
Both of these are less of an issue today than they were 15 years ago where a USB 2.0 audio interface added significant delay into audio and made it harder to get what you wanted out of the system.