There's a question of how familiar or unfamiliar a story should seem when it's set in a time and place that's different from what the reader is familiar with. Do you emphasize the differences or hide them? Maybe you add a footnote? But this assumes the reader needs a footnote. It's a way of highlighting the distance between the reader and the story setting.

Cultural changes are like that.

As someone who reads in part to find out about cultural differences, I think that maybe stories shouldn't seem too familiar, and I like footnotes and asides. Perhaps others will think them distracting, though.