For existing materials I would use them too with the exception as I said of Ivory and a few other animal products and again that's just my personal belief with no judgment. I would reserve harsh judgement on those who would kill for it today though
But if you get some old piano keys and make nuts out of it that's cool. I won't but that's my prerogative and I'm happy to explain why in the hopes that it makes even a small difference.
But it is a good point to note that in doing so it does inject some confusion into the market about how rare these things are and how much of an impact they are having and the possibility that it influences further poaching. But that will all end soon, once the existing materials are used up. In a way that's what we are doing now, we are phasing out.
So a test study like this is a cool way to demonstrate the possibilities of going forward as these traditional materials are getting phased out.