Hematomas on the ear are painful and inconvenient. 

Once they calcify without treatment, a person can develop cauliflower ear; a permanent deformity that increases the risk of ear infections. 

source: https://www.webmd.com/skin-problems-and-treatments/cauliflower-ear-symptoms-causes-treatments

USA wrestling has already took measures that makes ear guards mandatory for all competitors Schoolboy age and below.

source: https://usawevents.sportngin.com/dells-rules

The International Brazilian Jiu-Jitsu Federation (IBJJF) should allow competitors to wear ear guards as a safety precaution so that participants can enjoy all the benefits of competition without the risk of acute injury to the ears. 

As a result, more people would compete in IBJJF tournaments and the number of ear injuries will dramatically decrease.