Indeed. Not being familiar with that particular passage, my thought would be that he means, his uncle does not consider the status-signaling property of "beautiful" (and expensive) property to have any utility. This seems in line with Stoic reasoning.

I would also assume that by "slaves" he means, legal status aside, what would be called "the help" in a different era, i.e., the most visible members of a wealthy person's household and retinue. I'm sure that nobody was socially shunned because their salt-miners and ice-cutters were hideous to behold.