I'm guessing a rural mail carrier might want a RHD car and I wonder if the USPS or private contractors bought them that way when new in the US.
As to why someone would convert a car, in some countries only RHD cars are legal. That was the case in Australia, it was on the state rather than national government level but all the states but one outlawed LHD cars. I was in Australia in the nineties and they were in the process of trying to change the law for old cars at the time, or had in one state.
In some countries only LHD is legal, Israel is one, or was. I sold a whole LHD setup out of a Brit car I parted out to some Israelis in the early eBay days. The guy was emigrating from, I think, South Africa.
Having a wrong side daily driver is a huge PITA but for a fun car, especially where you sit over much modern traffic as in an A, it would be okay.