It's an optional process that analyses your files for things like bpm, temp, replaygain etc. These can be useful for specific purposes (like DJing, selecting music for different types of dances etc) and in some functions in the DSP studio (volume leveling for example).
If you'd find that information useful, let it run overnight for a number of nights maybe, instead of doing your whole library at once. Otherwise you can certainly disable it or never use it - you won't run into any problems.
