Seems you didn't get the point.  Let me explain again...

1]  Nxt is 100% proof-of-stake currency.  Why?  Because this lets not to waste tons of electricity and protects against 51% attacks.
2]  Proof-of-stake means that users must own some coins.
3]  How to generate coins?  Premine 100% and giveaway like Ripple?  No way.
4]  Let's transfer tiny amounts of bitcoins to my address.  More you send, more you get.  Looks good to me.
5]  Why send coins to my own address, not some unspendable address?  I need a way to send the coins back, just in case.  Or fund development of services to promote Nxt, if the total amount happens to be decent.

I hope this explanation will help.