They're an interesting middle ground between pure ephemeral dev environment and production environment. If your audience is the whole Internet, a Sprite won't scale today to serve it. But for most of the apps I'm building, the Sprite is actually fine for the foreseeable future. There's a ton of security automation stuff we're doing that a Sprite keeps up just fine with; the sandwich bracket I'm running downthread is also indefinitely fine on a Sprite.

On the other hand, if I took the sandwich bracket app and made it a generic "run a bracket" app and that app (inexplicably) got popular, I'd need to move it to a Fly Machine setup.