Ctp token is owned by ctptalk and that is where it is used. You hold and stake CTP, which gives you more power when curating. This is same as all other tokens like leo (inleo), alive (wearealive tribe) etc

CTPSB is a community token owned and operated by ctpsb community.
There is no link now. Previously, CTP was paid to delegators who delegated hive to CTPSB. But now they get paid CTPSB token.

Hope this clears the confusion.