Let me be more precise:
I'm not aware of any issues still happening with that, most of these issues have already been closed and I just closed a few more that are already fixed. (We don't use GitHub anymore for issue tracking internally)
The system actually rounds currency to two digits in the background since a while, as you can notice by some of the server log entries for that. The only one I've been able to reproduce is getting account values, but those are autofixed on a restart. That issue would be considered very low priority, which is why I assume it's not tackled at this time. I can't tell you the reasons for that, though. I'd assume changing the saving type requires changes that make it not desirable to do so and is hence avoided for other solutions.
But that ultimately is so detailed developer related, it's not part of the information I have. When I get a chance I can ask, though.