I guess their country location shouldn't be of any particular concern; particularly if paying by bank transfer?
It can be, to the contrary. Especially if you pay by bank transfer.
Some people do not want to have to make transfers to foreign countries and therefore prefer to trade with people from the same country.
- This way, there is no doubt in the bank's mind. There is no risk they will ask you how it is that you are sending money to another country. (It happens).
- Some banks require authorizations/confirmations in order to make a transfer to a foreign country. So you can easily waste a week with this process.
Others want to avoid specific countries. Personally, in my case, there are some I don't want to deal with. I stay in the EU, but I don't want to deal with some countries outside the Eurozone