Are exotic speaker cabinet materials overrated?

The vast majority of speaker cabinets are fairly cheap six-sided boxes with a fair amount of resonance as part the sound signature.  Eliminating resonance and flex is certainly beneficial, and should be a considered a step in the right direction in the pursuit of ultimate performance.  It should improve dynamics and reduce coloration through the most critical lower to upper midrange.  Lack of vibration from the cabinet can even help improve treble clarity.  

The question is how much of an audible difference does it  make...that’s a variable influenced by the rest of the speaker, the room and rest of the system.  If all else is equal and you substituted a poor cabinet with a really good one, it should be audible, but it’s only one contributor of the many aspects that influence the overall sound.  There are a lot of things that a high end company will do to improve sound of their products that many large conglomerate corporate mid-fi companies won’t bother with due to added cost with minimal marketing returns....my guess is that they (and maybe their followers) will argue that it doesn’t make a difference.  If you make every effort, things can reallly add up for an improvement.  If you make enough decisions not to bother for the sake of more profit...you have a mediocre product (even if it’s well marketed)....and that is often what separates mid-fi from high end.

Exotic materials are overrated yes but they never hurt anyone just a cost that can be needless or necessary depending on who you ask.

I've seen inert standard speaker cabinets. and resonance filled specialised cabinets... looking at you Borresen

Since a speaker is basically drivers, a crossover, and a box they’re obviously all critical.  However, that said if something needs to be pared back I’d rather have higher quality drivers and crossover and get by with a well-built, lower-tech MDF cabinet as pumping big $$$ into an esoteric structure probably has much higher diminishing returns as to its overall impact on sound (huge $$$ to develop and build with relatively small improvements, and not that they still can’t be very meaningful).  Some of my fave speakers muddle through with very good but relatively lower-tech cabinetry.  Could they sound better with more advanced cabinets?  Yeah probably, but how much better and at what cost?  Always trade offs. 

The correct answer is of course, as always:  it depends. 

Speakers Drivers are transducers, which is a device to convert one form of energy into another, the Driver converts electrical energy into Kinetic Energy.

Energy is constant it is never gone, but transferred to take on a new form.

Energy Transferral is also to be passed into the Speaker Cabinet of Structure for the Speaker to function.

Structural Designs for Materials used, or Materials Selected or designed for the purpose of being the Speakers Structure, are done with an intent to manage energies transferred, to attempt to have a Structure that has the least negative impact on the Amplitude released into the listening space.

The intention being only one sound is received by the listener not secondary generated sounds.

Certain companies use a Resin Impregnated Densified Wood Board to achieve their ideal structure, and I totally believe this is a very good material selection.