2 main purposes for having (especially audio file) playback control available from other software by inter-process communication:
1.When using some other software, that may be a video game, web browser or spreadsheet, while listening to audio with VLC, there would not be need to change software focus to skip back 4 seconds or adjust volume, if certain messages to VLC could be assigned to any keys within the other software.
2.Other software, especially games, could use VLC for it's sound effects by ordering playback of certain parts of audio files with millisecond precision. Simple homemade games would like to use this feature mainly because it would be easy for programming and compatibility. Big AAA games from big publishers would like this as an option among many, so that customers could immediately use their own complicated ready-made VLC audio settings for every game.
Just a few commands would go a long way:
1.Start sending time codes with x millisecond intervals
2.Go to time x1
3.Go to time x1 and stop at x2
4.Send volume as a number
5.Increase / decrease volume one step (that is defined within VLC)
6.Set volume to x
7.Short skip (that is defined within VLC)
8.Send length of audio in milliseconds