I went through the same debate with my 4K cd collection. I decided not to sell them for several reasons:
1. Even though I have a RAID, it is still not 100$ failsafe so in case of a catastrophy, I still have my originals
2. Encoding technology may change in the future so I want to have the originals
3. I just like the idea of having the CDs I can see and touch vs the virtual music that only exists in the realm of 0's and 1's (i.e. the matrix!)
4. I am a bit sentimental about my CDs. I have been collecting music for over 20 years and there are a lot of memories tied to each CD.
Anyway, just my 2 cents.
1. Even though I have a RAID, it is still not 100$ failsafe so in case of a catastrophy, I still have my originals
2. Encoding technology may change in the future so I want to have the originals
3. I just like the idea of having the CDs I can see and touch vs the virtual music that only exists in the realm of 0's and 1's (i.e. the matrix!)
4. I am a bit sentimental about my CDs. I have been collecting music for over 20 years and there are a lot of memories tied to each CD.
Anyway, just my 2 cents.