The currency in Gungeon is pretty rare though. I feel like I make more progress in Dead Cells to be honest. Even on a bad run I get through at least 3 levels and bank some cells in the process.
Well, in gungeon you usually get at least two items items added to the dungeon at the end of each run. I think Gungeon offers a lot more overall (it simply has a lot more items) but it does depend greatly on how well you do as you get more helix credits the further you go.
But it's not really the rate of new items that I find to be the issue, it's the point in time that it reinforces you. Gungeon provides that reinforcement at the end of a run, telling you about all the items that have been added to the gungeon. It gives you an immediate reason to jump back in and try again.
In Dead Cells, you get nothing at the end of a run. You just get told that you've lost your cells on that floor. It's a bad feeling, and there's no immediate reinforcement to push you back in again.
Even punishing games like Dark Souls offer that incentive to keep playing. When you die you leave your souls behind. So ironically, Dark Souls isn't all that punishing at all. It offers players an olive branch to keep going. At the end of a run, Dead Cells offers nothing.