someone mentioned justice vs financial gain - as assault is often a matter of he said she said and, let's be honest, the assailant is often not punished very severely if at all, suing the assailant may actually be more punitive than the assault laws.

Hit someone significantly in the pocket book sometimes "hurts" more than what the laws against assault permit.

Look at the OJ Simpson case, he beat a murder charge but was held responsible for his wife's death in a civil case.