I should buy one for my own but turns out you can put detergent between washing cycles, as long as you don't connect the dishwasher to a water line (well, I didn't check the other way around to be fair)

So I'm still weighting the convenience of turning it on and forgetting about it versus being able to buy the detergent for cheap at the mall...

Finding where you can buy the correct products for the cartridges can be quite the puzzle, last time I found a cheap-ish one with a "nice" 99€ delivery charge.