[ludbb]

There's a big gap in parsing the bitcoin blockchain vs parsing a local database.

The blockchain is a public ledger so any (encrypted or not) information you store there can be retrieved by anyone. Downloading it is very slow, and parsing it in a reliable way, i.e. using bitcoind's rpc, is even slower. So you'll want to build an index from it, which you'll happen to store in a local database. So after all that you end up with a local database and public information that anyone can access.

How is that useful for this purpose?