We still haven't built most of the stuff we want to build. We're not available in most countries; there are countless payment instruments we don't support; there's a lot of functionality we'd like to add. We want to do this as quickly as possible, which is expensive, and we assume that every round we raise might be our last ever.

That said, we've generally erred towards raising less rather than more -- most companies raise much more money than this in multi-billion valuation dollar rounds.