The reason it is important is because it paves the way. It is much easier to get approval of this new drug (natural cannabis extract, AKA Hash oil) in a country that already has approved it.
This is why they are going to Europe, I would think. It's gotta be easier to get it approved in Spain or UK if they already have signed off on the idea for one type of ailment, MS pain.
Remember, they don't allow for off-label prescribing. Meaning you can't prescribe GW's Sativex for PTSD and vice versa.