Seemannsdaemlack: And why isn't here a nice 90% discount for the whole Daedalic bundle like on steam? I would've bought that within a second.
Missed chance GOG, I would say.
People buy games, then proceed to not play them. Steam bundles require you to rebuy the whole bundle. GOG bundles do not and never did.
On Steam, if you're familiar with Daedalic, you're likely to have repeats and you're likely to have already bought the games you're actively interested in, so the effective discount is actually less than 90%, and it makes you buy games you previously passed over (yay free money for the dev).
If you're not familiar with them, you're not going to buy all the games at once at full price, so a massive discount entices you into buying more games than you will play if you only want a couple. Again, the company makes more money off you and rewards you with games which are free for them to give away.
Finally, almost-giving away games on Steam can result in more automated promotion from the platform and more sales and more money.
If GOG had a 90% off Daedalic bundle, it would have amounted to allowing existing fans -- those who are most likely to buy the new game at full or close to full price -- to get it at 90% off instead. This makes no sense and is proportionally a huge financial loss for the company.