in eastern world (and specifically mich of asia), we sit a lot more on ground, mostly because it is not as cold over in the more temperate climates of europe (and i said eastern because in western world it was mostly european settlers who brought their customs). a lot of times it would be easier to lay on floor as it is faster heat conductor than wood.

In this specific case, conditions still look far worse, and i was about to ask for some context as a worker on gold articles, he must make more than average worker. in that case, he would have something like a carpet beneath. also i do not see any jewellers furnace (or many equipments), so it might be because this is not his workshop (maybe outside his shop where he meets with clients)