When you sell people 6 quarters for $1 they tend to buy a lot. Useage is a poor metric here given the capital intensive nature of this business. What matters is can they do this in a way that makes money to the degree that justifies the valuation, and there they have not yet demonstrated this is possible.
The internal metric that they are using is they get $2 for every $1 in inference. So, if you discount model development costs, they are selling the tokens for more than it costs them to generate a token. And this is before they start integrating their advertisment networks into the model. They see something as high as $8-11 per $1 of inference once purchasing and advertisments are incorporated.