What's the point of Greed Mode donation machine?

[Colonel Vance]

Hello everyone
I just recently started my second savefile after reaching 100% and leaving the game for several months. I'm trying to unlock Greedier mode by donating into the greed machine, but I guess it's been changed, because so far it seems to make no sense at all.

I managed to put about 200 coins in, and the jam chance reached 14%
From that point onward I had about 10 or so games so far and the machine always jams after one or two coins, rarely three.
Is it just going to be like this until I reach 500 coins (in about 2 years, at this rate) or is there something I'm missing?

[Phosphophyllite]

Suffering

[Miranda ~]

If you are doing it with only one character, try doing runs with different ones, the jam chance as far as i know its only per character

[ModernSamurai]

You need to donate 1000 coins to unlock Keeper. If it gets jammed a lot, play with another character. It's not as bad as you think it is.

[Luna]

jam chance is per character so if its jamming that much you have to use a different one

[Colonel Vance]

I'm playing Co-Op with a friend, we have characters we like to use often. Perhaps that's it then, thanks.