SaaS businesses that are priced by usage. Pricing by subscription ($x/month) or by users ($x/user/month) is much more easier, more predictable, but makes these

SaaS businesses that are priced by usage. Pricing by subscription ($x/month) or by users ($x/user/month) is much more easier, more predictable, but makes these unattainable for a large chunk of the global market. VC funding means revenue optimization, which leads to either of the above 2 revenue models (or some variation thereof). Charging your customers like how tarsnap charges its users means you won't ever make a lot of money, but it can be a sustainable business.