The pass includes a set number of credits that can be used until they run out (usage-based).
Example 1 (simple): You run regular events priced at £10 a ticket. You create a Pass valued at £100 which gives your audience access to 11 events (buy 10 get one free!). Purchasing the pass gives the customer 11 credits, which they can use to book 11 events in total.
Example 2 (more complex): You run a range of events, from simple to elaborate. A pass could be worth 100 credits, with your headline event worth 50 credits. Then, one event could cost 10 credits, another 20, and others just 5. In this case, your audience needs to balance how they spend their credits.