Why not Tor?

Tor provides a proxy which anonymize your IP address from the server.

However it is rumored that NSA is try to controlling the Tor network. Tor's anonymization is achieved by relaying your encrypted packet through three or more relay servers. Unfortunately, if your entry (first) relay and exit (last) relay are operated by a single person or entity, that entity can track your packet. Tor is an excellent service, but it does not provide cryptographical nor mathematical security.

In addition, if you want to access to the private (authenticated) endpoints on the server, the server will learn who is accessing by your authorization token (like session keys). In this case Tor does not help privacy.

With EllipticPIR, you can query to the server in a cryptographically and mathematically secured way even if you are using some authentication. This characteristic cannot be achieved by Tor.