They are right, no one ever does that. Their reasoning for the imperial system being practical is stupid though. The reason it can be practical is that its useful to have a unit the size of a foot sometimes. Metric is better in general, but there are aspects of the imperial system I would miss if I switched entirely. I just use imperial in casual conversation and metric for anything important.
edit: To be clear I’m not saying conversion from feet to miles isn’t a problem because no one does that, its the opposite. No one does it because its a problem.