Great point, and you're right that's easier if it's already cloud-based. But with ngrok-type utiltities (and good old SSH) there's nothing stopping us from saying "hey, check out this weird bug on my local instance -- here's the url/ssh hotsname." The downside is that it's often harder to spin up multiple locals than multiple cloud instances, and so it's harder to publish a url for the team to play around with for a day ("I'm building this new feature, but I'm not sure about the UX, what do you think?"). But IMHO the benefit of being able to nuke and recreate a dev environment in seconds (rather than the ~10mins it sometimes takes for a cloudsql instance to spin up) is worth it.