Stealing this description from the base Jag unit:

The Jaguar was Atari's hope in joining the console market again after so many years, but it ended up being one of their biggest flops of all time - It was touted as a superior 64 bit machine, but the specs honestly had it running games closer to its 32 or even 16 bit competitors. It was notoriously hard to program for, so there was a lack of third party support. Even then, most titles did not even come close to tapping into the full power of the system.

Even though the Jaguar was in the spotlight with its bizarre and edgy marketing, it just couldn't grab a foothold against the PlayStation, N64, and Sega Saturn. It died after a quick turn in the industry, lasting only 3 years on the market with a very small library.

When it comes to the add-on CD unit, an extremely small amount of games were developed for it, and most were used to either show off some (honestly good for the time) full motion video or CD audio soundtracks over some not-so-technically impressive titles.