All of David Shepherd's Comments + Replies

Yeah good point, I'll try to figure out something less rough.

The main source of inaccuracy is that I'm not sure what the right counterfactual is for someone doing a Wave payment. It's probably some proportion of each of: not doing the transfer at all, using some informal method, and using our main comptetitor. For simplicity in my estimate I just assumed that all transfers would have been done using our competitor.

Aaron Gertler
The "all transfers use our competitor" assumption seems reasonable enough; I don't think the estimate has to be very rigorous.