Are u fetching data from blockchain.info api ?
No its a blockchain wallet api client to send and receive payment from a blockchain wallet account. You can find more details on the official Blockchain Wallet API Documentation.
Well, it looks very similar to blockchain.info send/receive API. Moreover, as I can see, it is checking address balance using password in the wallet api. This is redundant & insecure in my opinion. It can be viewed directly...
https://blockchain.info/q/addressbalance/12c6DSiU4Rq3P4ZxziKxzrL5LmMBrzjrJX
You are right. I think the blockchain wallet api webservice is for merchants. So it is possible to create accounts for the merchant users and the users don't have direct access to the wallet. It's also a feature of the blockchain wallet api webservice.