You explain to Leon that you can’t make revenue a primary metric for experimentation because it’s not tied directly to an action your users take on a page and explain that you need to tie experiment goals to changes that can be directly measured. But you explain to Leon that you can can set up revenue tracking to track revenue as a secondary metric. When he asks about how revenue tracking works, you explain that revenue tracking can track total revenue from purchases or other events on your site and attribute the amount to a specific experiment and variation. With revenue tracking, you assure him that you will be able to see the revenue earned per visitor, revenue per paying visitor, purchases, and the total revenue earned per variation on our results page.
Leon's satisfied with your responses and excited to see how the first experiments will turn out. He's delighted that, even though you can't track revenue as a primary metric, you'll be able to directly tie the results of your experimentation to changes in revenue. That will make his job with the higher-ups much easier as he justifies the experimentation process.