QM is a mathematical model. Many worlds is an intuition to understand that model. There is a pedagogical question on if many worlds is a useful mental model to have. There is also a philosophical question of if many worlds better captures the essence of the model relative to Copenhagen.
We can also flip it around. Why should we think of QM in terms of the Copenhagen when it makes to testable predictions.
> If the Born rule were found to be violated, it would invalidate Copenhagen but not MWI, which IMO means Copenhagen is more falsifiable.
All quantum mechanical interpretations depend upon the Born rule. A violation of the Born rule would rule them all out, except perhaps Bohmian mechanics which allows the possibility of non-equilibrium states, but we have no idea if those can be created.
I mean, the pi/tau thing is _purely_ aesthetic. That's a big waste of time for sure.
Having a more coherent metaphor for the evolution of quantum systems might help with physical insight, though. If e.g. the universe isn't differentiable across spacetime, we need a better understanding of GR. Many worlds insists it is differentiable (and local), so thinking that way could help integrate the two.
It isn't an important thing, but pi/tau is an unrealistically silly thing to compare it to.
You can still believe it if you like, but its slightly less useful than trying to convince everyone to replace pi with tau..