Understand that 'function as' indicates an unusual or temporary role, not a permanent one. At the camp, my phone functioned as a flashlight.
Pro Tip 2/3
Context Variation
The meaning can differ depending on context; consider surrounding words for proper interpretation. She'll function as the interim director until a replacement is found.
Pro Tip 3/3
Metaphorical Use
'Function as' can be used metaphorically to describe something behaving like something else. The garden wall functions as a wind barrier.