I like that a lot, Monzo makes your money more accessible, which of course is a good and bad thing! A couple of points I’d like to see, sorry if this has been covered above:
Double Lock / Power of Attorney - This could work great with a joint account, once a lock is put into place it takes two people to agree to remove the lock. You could even give one user overall authority for the lock, we all have that one friend that needs help to not spend
Timed lock and payout - I think this could potentially be coming with the timed pots feature I am sure I read about. However lock your money away until X, then it moves from a pot to a current account. I have some expensive school fees I need to remember to save for / move just before the DD. That would be very useful.
Better interest - How about earning a few points more savings if you commit to a lock for a period of time?