It does matter in the UK for certain types of aircraft.
The PIC must be able to reach all of the controls, so for aircraft such as the Pipers Warriors/Arrows etc the right hand seat is too far from the fuel selector.
Also you can only ask a passenger to change out of reach control such as the fuel selector on your behalf if you have an Instructors Rating.
Can't remember where this exact law is written but our instructors are not allowed to fly solo from the right hand seat for solo ferry flights.