Why do so many artists have synesthesia?

Synesthesia is the awareness of relations between different types of experience, with experience defined as sensory data.

To be synesthetic is to have a mapping from one type to another, as in the examples given of Natural numbers -> personality archetypes, audio -> video.

After a glimpse of it an an emotional moment, I intentionally developed my synesthesia. I think others could develop it if they like. However, rationalism is an obstacle preventing most from experiencing synesthesia. In order to e.g., see a high C as red, you must be more trusting of your subjective experience than reasons.