I use offline maps a lot. The article mentions a major reason: traveling, especially abroad, with limited or no data. It also comes in handy when we drop out of cell service, which happens more often than I'd expect outside of major cities in the US. My favorite app for those use cases is Organic Maps, which lets me download maps by city, state, or country.
I use offline maps for hiking too, but it's such a different use case that I find I want an entirely different map type and UI – one that focuses less on roads and directions and instead surfaces tools for route-planning and managing tracks and waypoint markers. Gaia's long been my favorite app for that.