Yeah I think some of the appeal is that you’re playing with a deck to test out that generated deck, rather than testing out a designed deck where you’re testing the player’s skill at building a deck. If it’s a deck of your own making then I can see how players can feel more personally invested and more competitive because of it. Keyforge avoids the feeling that your deck’s weaknesses are your own fault and gives you a scapegoat for your failures.
The counterargument is that it also loses the sense of pride a personal deck can provide, which is something that appeals to a different kind of player. It’s nice to have a card game that appeals to a different subset of players, which seems like the thing that allowed Netrunner to be so successful!