I think you need to read a bit more about i2p, its designed for more than just filesharing. its a darknet anonymous network, kind of like onionland but better. i2pbote is a great p2p serverless email network built on top of i2p with encrypted headers. I use it myself and integrated it into my darknet exchange. i2p eepsites support multihoming and easy to use router connection limits to help minimize the ddos issues with tor marketplaces.

saying that i2p wont protect you from the NSA is silly and oversimplifying things. The question to ask is "does i2p remove the link between altcoin spend signatures, blockchain data and address geodata from the clients true IP" the answer is yes it does. Im not sure how to reassure you that i2p is immune to the NSA, but good luck demasking the IP of an anoncoin i2ponly client.