Afterpay Valuation, page-3088

They have expanded into 2 new markets with no knowledge of whether it will be an absolute failure or a success. It is a success. A whole lot of this uncertainty is gone
Added to this is the repeat customer in ANZ. (It isn't a fad), the cash-flow positivity of the ANZ business, the lack of feared regulation and lack of fierce competition from incumbent businesses like banks and credit card.
Also add to this the experience during Covid (recession isn't as bad as thought for the business).

These events (or lack of event) reduce the risk discount applied to the future forecast cashflows when valuing the business. Hence the increase in price.