Hey Robert 
Welcome to the community!
Thanks for the suggestion! This is something that’s been requested before, but because the money you put into your Savings Pot is held by the provider you signed up with (eg. OakNorth or Investec), we need to give them a heads up so that they have the time to move the money back into your Monzo account.
Withdrawals from an Easy Access saving pot should come through by 5pm the next working day, but if there’s ever any delays then you can reach out to us via the Help tab in the app and we’d be happy to take a closer look!
You can also vote for this feature here if it’s something you’d really like to see in the app: Instant withdrawals from savings pots