@GatVlieg makes a very good point: the official smart lighting automations are eligible to run locally, but only can run locally if all of the device handlers being used in the automation are also eligible to run locally. And at the present time that is limited only to the officially published device handlers, and not all of those.
For example, Phillips hue bulbs are not currently eligible to run locally, so if you include even one of those bulbs in your smart lighting automation, that particular automation will not run locally. 
Depending on which server your account runs on, the links to check what is eligible to run locally on your own account are different. The community-created wiki has all six of the links: