We have had an item on our roadmap for a long time (basically since the beginning) that would allow license trading similar to what EVE did with PLEX.
We removed it in favor of the PRO license time gifting feature.
We are aware that is is possible to pay with real world currency for these gifts, but we don’t support or recommend it. In fact it is in violation of our ToS (§3.7).
One could argue that trading in-game materials for real world currency has been possible before, the license gifts are just another item.