Well... deep question. SCCA has many different licenses.. I guess which one are you asking about?

SCCA worker license... everyone that is an SCCA member has one
SCCA SOLOII license... costs $15 or so and is worthless
SCCA ProSolo license... Need if you compete for points in Pro Solo
SCCA Competition license... Expensive, and needed to road race with SCCA.

There are more...