This is a terrible "solution". Changing a customer's email address should be basic functionality that Squarespace provides, we shouldn't have to pay another $29/mo for a 3rd-party integration to be able to do this (esp. not when Squarespace is already more expensive than other similar platforms).
My customers are on a subscription plan so they would need to cancel their subscription just to change their email address, and then there is the risk they won't bother resubscribing.