Originally Posted by
Corporal Clott
The hat is required to wear a badge with the Sovereign’s Crown (in our case Her Majesty The Queen).
When serving personnel salute an officer, they are acknowledging Her Majesty the Queen as Head of State and saluting the rank the officer holds (the Queen's commission) rather than the individual themselves. When an officer returns a salute, it is done so on behalf of the Queen.
So it most definitely serves a purpose unless you want that badge tattooed on your forehead or pinned on it - which might be a bit messy or painful…
Your explanation just shows it serves no purpose, other than one you've imagined for it.