1 point for a win and half for a draw is "just" a convention, matter of habbit.
In some early tournaments /London, maybe, I don't have time to google now/ it was 1/3rd for a draw.
"It is not fair that 2 draws are valued equally as 1 win" - that was the reason they introduced 3 pts in football (soccer), and it was often favourable suggestion by many GMs, also Fischer.
I like it, 3 pts for win, it punishes quick draws, favours attackers and those who play to the "naked Kings".