That's good for you. Your very specific example is one that seems to worked out for you in your very specific case. My point is that sometimes usage isn't so easily measurable and is multi-variate. You might not be able to calculate the cost with simple multiplication, especially when there's many SKUs. Say you offer 100x services, but the customer only needs 10 of them. Are they going to look through the list of your 100 offerings, mapping their requirements to what you offer and hoping the math works out? Probably not. It's way easier to talk to an expert at the company and understand if the product is a good fit and get a proper quote. A good sales meeting saves both sides so much time and money.

> And giving a customer a quote so they don’t have to understand the product? That just sounds like a bad idea all around…

You've fallen into the classic HN trap of assuming that everyone that uses software is also a software developer. Sometimes, you're selling to the HR rep or a CxO. They don't have to understand the implementation details of the product to understand whether it meets their needs and if it is a good investment. If you have to go deep into API calls while explaining the price, you're going to lose the sale.