Looking for sensible explanation, page-75

"you then just have to look to see to see when the thesis fails to cut and run....eg. If only 3M users in Us by year end this is a major problem."

Disagree on this one, while it will mean the user base is not growing exponentially in the US, it will mean the user base is growing 220k per month, assuming 1 million at March end. Keeping that linear growth, 2 years later the US base will be 8.3 million strong, and conservatively assuming 3 million *active* customers in ANZ at that stage too we'll have a total base of 11.3 million end of 2021 i.e. mid FY2022. With average yearly spend per customer by that stage of $2k (currently sits at ~$1800 in Australia), this would give FY22 GMV of $22.6 billion, exceeding Afterpay's target by 13%. 

While this wouldn't be exceptional, it wouldn't be a major problem assuming global NTM of 2% is attained.  CAGR of 79% from FY18 to FY22 is not too bad either.