"Le coup du milieu" refers to the slug of kirsch that folks either dip their bread cubes in before plunging into their fondue or sip alongside. Seen a few of these mini fondue pots ("petits caquelons"), but never as a set with glasses. They'd get in the way when you're dipping your bread!
I reckon someone married up the two components because the colours matched, more or less. Then they could serve the kirsch in the glass, allowing the diner the choice of either drinking it straight, or pouring it into the little pot for dipping purposes - or both, hic! :ho:
The glasses look Czech to me, too.