I have a few actors myself where the use case is not the typical "scrape and return results" workflow. They may be automation tools or research tools where the number of results/events is not predictable. For these scenarios, PPE + usage-based pricing is the only way to price them correctly, even in the long term. I hope Apify doesn't remove this option in the future. If it does, the only alternative will be to reimplement usage-based pricing within PPE by tracking things like proxy usage and CPU time inside the actor itself.