I don't really want to promise anything we haven't shipped yet. But my perfect cloud service (a) charges me when VMs are alive and (b) gives me the tools I need to create/remove/stop/start/suspend/resume VMs based on either network activity or metrics.
One flaw of Fly.io right now is that it's relatively expensive to run a side project in 10+ regions. Most apps benefit from 10+ regions, but $50/mo to try it out is prohibitive. We want to make this more accessible.