A technician might be incredibly good at doing things like hooking a mobile app up to a REST API, building database frontends, and building on top of an established system. The engineer on the other hand is able to do all of the above, but is also someone you could trust to give a high level overview of the system as a whole and expect to come back with a considered approach to implementing it, taking into consideration things like fault tolerance, how an operations team would interact with and monitor it, and where to make tradeoffs between an ideal implementation and time/money limitations.

At least in my mind there's nothing to stop a sufficiently motivated technician learning the necessary skills to be considered an engineer - its not about credentialing, but about having experience that could come either from a college course, or just from working in the field for long enough to have picked it up.