This issue has been done to death.
It’s just another pointless rule. The pilots involved in fuel exhaustion or starvation incidents aren’t in that situation as a consequence of a lack of rules.
I’m not going to be doing a precautionary landing into a “field” to ensure the entirety of my fixed reserves remain intact rather than land at my planned destination with less than my fixed reserves intact. And I won’t be declaring a MAYDAY when I calculate that I’ll land with less than fixed reserves intact.
The arseclowns who make these rules can go their hardest, accordingly.