No idea tbh. Panini is an Italian company, so I would have expected them to be the most popular in Italy, but when I look for Seviper Kraks (and Waps), I almost always come across them from French and Spanish sellers, and almost never Italian or UK sellers where they were released as well (a.f.a.i.k.) - I’m not sure what other countries they were released in tbh.
As for this French source, I actually came across it by accident before dinner today when I was trying to search which sets there were for the Pokémon Staks, since the set @Kob showed in his/her pictures didn’t contain the Seviper I have, so I knew there had to be more than one set.
It’s actually a great source, and I’ve learned some new things myself writing my comment above. 
I still have it on my TODO list to post all my non-TCG Seviper stuff (stickers, pogs, posters, etc., including these Staks, Kraks, Wapps, Metal Tags, Action Flipz, Lamincards, Amada stickers, etc. etc.), similar as what I’ve already done for my Seviper plushies and figures.
But more stuff keeps coming in, and it’s difficult to find information on some of these items, so I haven’t made the time for it yet…
Greetz,
Quuador