Tom has touched on the concept before in one of his comments too -
Are you requesting an in-app option to select the account, that you want to use to pay a merchant, for an over the counter transaction though? That could be handy
Based on the comments from Monzo designers that I’ve seen up until now, my guess is that Monzo would want to come up with a way to automatically select the suitable account / pot to take the payment from, rather than the user having to select it manually for each payment, based on the merchant, time of day etc. through a process similar to the automatic categorisation of transations.