I'll use twitter. It is HTTPS. If I'm paranoid that it knows my IP - I'll use Tor.
SO... u think twitter is secure? have you read all that things about NSA obama and all that friends?
There is a sentence about Tor which is older, more reviewed and have bigger community. And it is free and open-source.
I actually agree with you when you think about messaging as a stand alone feature. I look at it this way. Secure messaging is just one tool I use when completing a fully independent Nxt transaction. Meaning, at one point you will be able to browse products, communicate with seller, initiate purchase, put Nxt in escrow (receive item), send funds, leave feedback, all within Nxt client. That is just one example of hundreds that could be used with Nxt secure messaging.