a thing to note, is that if bitcoin could work without the blockchain, it would be completely anonymous, definitely 100%
also another little off-topic note(but worth consideration), the first comment is the reason for the slow adoption
"last time i checked, it was also pretty easy to send USD, EUR, JPY , etc electronically."
The transfer of value between two points in the world can be done fast via electronic means. However, there is a big difference between the bitcoin and fiat. Fiat requires identification, credentials and other personal details, and the process of confirmation of identity could be long--sometimes it lasts for days, whereas in bitcoin, the user who will send the money only needs to know the receiving address of the person he's going to send to and that's it, the transaction could be processed by miners and displayed in the blockchain, making it public and thus adding to the validity of the transaction that's been done.
Blockchain is the technology invented so as to record all the valid transactions that was made inside the bitcoin network.