The Compact Disc (CD) is an aging format that in time will no doubt go the same way as vinyl or cassette tape. However, there are more reasons than just old age why you should consider ripping your original audio CDs to a lossless audio format.
Probably the top reason why people convert their physical library to a lossless one is to protect their investment. You may for example have several CD albums that would be particularly expensive to replace, or almost impossible to find again due to their rarity. In this case it makes sense to store these as a lossless digital backup so you can re-burn them to blank discs which will be audibly identical to the original.
Another common reason why you might want to make an identical copy of your original CDs is to be able to convert to different audio formats without your songs suffering from an excessive drop in audio quality. The problem with storing music in a lossy format like MP3, WMA, AAC, etc., is that if you then convert to another lossy one, this degrades the audio quality even further -- the technical term for this is generation loss. Having perfect master copies of CDs therefore ensures that you'll always have a version of a song that is identical to the original..