I know nothing of this world of comics, I guess because it is essentially part of the US culture and did not penetrate much of Europe.

There has been a number of investigative shows arguing the valuation of collectibles in general (comics included) is largely driven by money laundering.

Is it some kind of conspiracy theory of is this legit ?

As usual, generalising all of Europe based on your individual country is a mistake as there are some Euro counties where comics are quite popular. France, Belgium, Italy and the UK all have thriving native comic book industries, and I have Swedish friends who tell me Donald Duck comics are very popular there.

I imagine a pristine 1st edition Tintin or Asterix would be quite valuable.

I remember as a kid that Superman #1 was going for thousands of dollars and we just oohed and aahed.