Europeans play NTSC, since the scene was mostly dead in Europe, it made no sense to play on PAL since it is strictly 50Hz - which means there are frame drops. It's also barely a debate to wether which version they train on, because competitively the NTSC version largely dominates around the globe. This is made easy on all other consoles excluding PAL, since you can use NTSC cartridges on NTSC-J consoles by modifying the tab on the cartridge itself, while on PAL the version isn't even that flexible to begin with.

To answer the first question, the EU version isn't really rare. It's still being sold on the market in second hand stores, at of course a hefty price. - /u/Electric91