I just saw "limited discount" in GoG for the first time, isn't it great way to boost sales?

Definitely not the first time. They had insomnia sales a few years back. Was quite a success back then as well.

They've had some limited time sales running for a bit now, but the insomnia sale return is from today I believe.

It probably has a better chance to generate sales than their attempt with mailing individual discount codes.
Anyway, this idea isn't new. Fanatical does it all the time with their star deals. And I think they managed to convince me once to accept such an offer.