"Is APT actually overvalued?", page-7

Certainly a risk. However the chart above is comparing established profitable businesses growing @ 10 - 20% per year (or less) with a business growing @ 50-100 % per year & about to generate positive cashflow. I don't think the comparison based on PE is accurate, however risk off market will definitely affect valuation (shorter term)

All listed above are not going to have double their customers, 10 x their accessible markets in the next year or two.

It is, however a risk that Afterpay doesn't perform as well as some holders think.