Check out my first published board game: In the Name of Odin!
that's also a way to discard a not useful card for you, as you draw back right after.
Yes, exactly. This mechanism works both as a "take that" element to the game (you can try to deduce what card will hurt a player the most, instead of letting the random draw decide), but mostly it's there to allow you to get a replacement card in preparation for your turn. Which is why, for the most part, it makes sense to get rid of a card that you know you're not going to do anything with - especially if you're the next player in line.
Once everybody takes a card from the offer, it's refilled again, so it's almost like two replacements of the offer for free, which allows you to get some new cards on the board if it's been stuck for a while.