I do. Technically I have a stash (maybe 100+) of the thin-foam cups and lids to go with them. You ask why? One really simple reason - the thermal conductivity

I do. Technically I have a stash (maybe 100+) of the thin-foam cups and lids to go with them. You ask why? One really simple reason - the thermal conductivity is really low both due to low mass and the material. By comparison, putting the coffee in one of my nice Illy collector cups that I've had for a quarter century (and now are probably worth $100-150 per cup) causes some dissonance when I drink it. The cup is cold on a relative basis to the coffee. And my espresso machine does not have a cup heater. And making a cup that hot would be uncomfortable to touch. Ten years ago, I would have thought this was madness, and now I worry about not having access to the cups anymore (I got them through a friend who ordered them commercially). Once you get used to drinking out of such a cup, the coffee is the entire experience. There is no real notice of a cup getting in the way of the frothy goodness of the coffee between the cup and your taste buds.