What were IP transactions supposed to be useful for? Besides sending BitCoins using wallet addresses, there used to be another way, through IP transactions as described in the wiki.

The disadvantages were obvious (man-in-middle attacks etc).

However, were there any benefits (to the individual or to the whole system) in using IP transactions?
First, it needs mentioning that this functionality has already been removed from the original Bitcoin client.

Here is the GitHub pull request removing this functionality that has been accepted 2 years ago. The wiki page you refer to seems outdated.



The only known use for IP transactions I could find is the one mentioned in the pull request by gmaxwell:


  Aww. The removal of this would mean we can't run a lottery for nodes running the most recent version of bitcoin as an incentive to make people upgrade. :)


Another use I can come up with myself would be that you could use the DNS system to create a human-readable address to your IP and use that as your payment address. F.e. I could use bitcoin.stevenroose.be and put the IP address of the computer running my Bitcoin client in the DNS table for that record. I could then tell people to send bitcoins to that address. However, this method would require a PC to be permanently running and connected to the network in order to be able to receive bitcoins.