dyscode: Well, I wrote Obsidian support to answer this question, They surely know if they get money from that site or not.
If they're doing something illegal I will replace the post with a warning not to use that seller, but Paradox are the publisher not Obsidian. They will have to trace the keys back to the wholesaler, but no matter what I expect Paradox will say "
we only recommend buying from an 'authorised' retailer." I will be genuinely surprised if they say anything positive about it.
Remember that publishers don't like it if they can't completely control prices, but the EU commission is moving toward reasserting our rights as EU citizens to have free movement and price competition for digital goods, just as we have for physical goods.
You may also consider this: Greenman Gaming started out as 'unauthorised' but are now one of the go to places for 'authorised' sales. SimplyCDkeys are another that people accuse of being 'illegal' but it's merely a website by SimplyGames, who have been around for years selling consoles and physical copies.
I know there are real problems with stolen credit cards etc being used to acquire keys, I wouldn't pretend there aren't, but even stores like Amazon EU (fake AMD processors) and Newegg (dummy Intel processors) get caught out from time to time by criminal elements within suppliers, but that doesn't stop us using them.
I used to be very wary of these 3rd party sites and in the past would not have considered using any of them. However, a lot of the '3rd party' sites have now been going for years. I think ones like CJS would be taken down a long time ago under UK/EU law if they were selling illegal copies.
I feel we've reached a point where saying a blanket no to independent key sellers is akin to saying a blanket no to buying from a high street independent.