On the one hand, it offers you the possibility to copy the content from an audioCD to the HD, that's what's called rip an audio CD.
On the other hand, you can use it to convert audio formats. It supports the following audio formats and convert from and to:MP3, MP4/M4A, Ogg Vorbis, ACC, Bonk and FLAC.
Finally, it integrates information from freebd.org, that will be very useful when ripping audioCDs, because you won't have to type the information of the CD, the program will do it automatically. Yes, BonkEnc will download the information about the CD and will save it in the ID3 tags: title, artist and even the album cover.