Hmmm purely a confidence and aesthetic thing for me.
Does my 42mm edge, 25mm toe and 20mm shoulder bat ping just as well as my 36mm edge, 21mm toe and 18mm shoulder bat? Yeah I think it does, or the difference in feel anyway is minimal either way. Do I always pick the bigger bat to walk out to the middle with? Yeah I do, it gives me a bit more in the mind and that's all I need.
I'm also a sucker for a nice even yet big shape. The GM Zona that came out years ago now makes me feel ill, along with what some people are doing now to get the big edge size, making them huge and just carving out from above the middle to the shoulder. A nice flowing line from shoulder to toe is my preference anyway. I wouldn't say I hunt specs, but I do hunt a "nice" (in my eyes) profile, as an example I got a small edged warner from B3 a while back (35mm edge, 70mm ish spine), initially bought on the wow factor of the specs but I actually didn't like the look of the profile so ended up shifting it on, in theory the higher middle would actually be my preference. lesson learned so last week when I was offered a 30mm shoulder, 35mm edge and big looking toe, but the spine was pretty much flat, again not my preference, so I passed. Would that have pleased the spec hunters or are they just very specific in what they want?
In your case Jonny, what's the option as a maker? I can imagine it is a bit frustrating as it's almost trying to teach people about wood properties during a sale? Or do you offer them alternatives? As in yes I can make your bat to those specs but a) it might take months for the right piece of wood to come through and educate or b) yeah I can do those but it'll have to weigh X or I can make it thinner etc?
I agree the gauge coming in has made things a bit harder, it's given people a max to aim for in what they want because in life (the max is the best...)