Part 1 is bandwidth prices vary tremendously by location, but clouds would like to have customers in expensive regions too, and if US overcharges at 100x, and Brazil overcharges at 25x, the customer will only have to pay 2x for bandwidth in Brazil. Not a lot of cheap hosting in Brazil, from what I've seen, but there are a lot of users in Brazil, attracting cloud customers justifies putting more cloud hardware there which benefits the cloud.
The other part is that bandwidth is easy to measure and broadly correlates with general usage. On a shared system, you can't really meter watt hours, but you can meter bandwidth. Bandwidth charges are how the difficult accounting is reconciled so that the cloud can charge enough to hit their desired margins. If bandwidth was just a cost plus, other things would cost more; if everything had to be cost plus, accounting would be much more difficult for everyone (and it's already pretty non transparent)
Part 1 is bandwidth prices vary tremendously by location, but clouds would like to have customers in expensive regions too, and if US overcharges at 100x, and Brazil overcharges at 25x, the customer will only have to pay 2x for bandwidth in Brazil. Not a lot of cheap hosting in Brazil, from what I've seen, but there are a lot of users in Brazil, attracting cloud customers justifies putting more cloud hardware there which benefits the cloud.
The other part is that bandwidth is easy to measure and broadly correlates with general usage. On a shared system, you can't really meter watt hours, but you can meter bandwidth. Bandwidth charges are how the difficult accounting is reconciled so that the cloud can charge enough to hit their desired margins. If bandwidth was just a cost plus, other things would cost more; if everything had to be cost plus, accounting would be much more difficult for everyone (and it's already pretty non transparent)