That is sort of my point, however.. I take a very cold and simplistic view of magick.
To me there are no gods etc... and no elements. Instead there is one source of energy, i dont believe it is pure or holy or godly etc... it just IS in the same way that heat energy just IS, it isnt bad or good or godly, it just exists. From there i believe we take in some of this energy sort of like the way we breathe in part of the air around us, and then i believe that we "filter" or "program" the energy, so for example if i were to cast some protective shield over myself because i felt i was being attacked by a psychic vampire i would instantly think of a RAGING inferno of flames all around me and hence surround myself with "fire" energy, the energy is flaming, it isnt hot and it doesnt come from some god like fire elemental, but what it does have are the characteristics of fire. For example, if you stick your face in a fire, you get burned. If you try to mess with a fire, you get burned. It is protective, burns away darkness and scorches the eyes and senses etc.. so that is what my "fire" energy would do. It wouldnt BE fire, but it would be LIKE fire.
In a similar way air, as a protective shield, would perhaps hide you in a whirlwind of activity, the swirling nature of a hurricane would fling the negativity away from you etc... You wouldnt be surrounded by air at all, or even by an "energy hurricane" etc.. but if your shield was done correctly then merely having those feelings inside you would mean that if i were to attack i would be flung away or if there is such thing as sight in the spiritual world then i wouldnt be able to "see" you properly. If you were to attack me then you would suffer pain in return (like you would be burned if you attacked a fire) etc...
With regards to "being" an element i think it isnt a case of choosing but merely your emotions and attitude and it is just a way of summing it up in one word. Again, back to fire i would say that a "firery" personality is warming, protective, loving to those who treat that person well and on the flip side they are liable to spontaneously erupt, either by going out and spending £2,200 on a camera one day (yup, done that) or indeed in a fit of rage at someone who cuts them up (done that too

) and if you annoy a fire person then you will know it. So it is easier for us to say "oh, he is a fire person" than say "oh he is protective but if you annoy him blah blah blah"
To me the elements are worthless in a spiritual sense but are instead metaphors for how we act in life and how our energy feels and works. Some might prefer to hide themselves from an attacker, others might prefer to stand like a mountain in the attack without being harmed, others might want to destroy the attack until nothing remains and others might want to gently but firmly push the attacker away and keep them away with a constant and firm force.