I like the idea of pots however all they do is sit there and be visible making the cash easily accessible. A few suggestions then:-
Don’t make the contributions visible at all times so it is easy to “forget” you are actually saving. Maybe an option to turn the notifications off from the main balance screen?
Set targets for pots such that it reminds you of the goal / item you could be saving for?
Use the entire fund for a crowdfunded investment pot. Monzo can then invest it in either a high, medium or low risk investment, we (the users) select what risk profile we want and (hope?) to see the funds grow. I would be less likely to withdraw the money if there was a remote chance it would increase.