Bloggs - as Akro says, I also carry a variable reserve for a PVT flight - point being, there will always be a scenario where there is a need to use the fixed reserve - planned or not. If your argument is that you should be able to plan to never use the fixed reserve then why not make it 1 minute or 5 minutes? What's the point of having a 45 minute reserve?
You do understand that if you declare a PAN PAN for encroaching on your final reserve (or whatever CASA arbitrarily decides you require on board) then you're committing an offense? And this doesn't concern you?
For a remote area operation, there is also a risk to safety in diverting to an alternate and potentially needing to stay overnight in extreme conditions waiting for the required fuel or help to turn up.