The use of elements in magic is working with symbolic archetypes rather than as the literal elements. There are many concepts which are treated this way, from elements to general lore.
Each of the archetypical elements has certain properties. Working with that element is working with those properties, according to whichever tradition or teaching is being used with that work.
It is the same way that flight in some tales may be used to represent enlightenment or knowledge, or may be a symbolic means of describing spiritual journeying such as Astral Projection.
A lot of parallels can be drawn across many origins of lore in this fashion. Some things might be addressed as seemingly literal when they are symbolic in stead.