"Seems it's designed to encourage people to drive between shops."
Even if you park "in front" of a shop, it's farther to walk into the shop than from Roseburn Place to Roseburn Terrace. How come they don't all go bankrupt if people have so far to walk?
It's actually not bad for bicycles. Good off-road connection to the Innocent Path, and while there are a lot of cars on the car park, speeds are rarely above 10mph. They installed bike racks at various shops (blue dots on Open Streetmap) though not everywhere, but you can cycle nicely between shops (though the only shop I go to is B&Q, the others don't seem to have anything useful).
Actually the car park is ideal for learning to cycle in traffic. There are enough junctions and cars from all directions but all very slow, ideal training ground.