Some people write documents that can only be clearly presented on a 15" or larger display. Maybe a comparison table with a bunch of columns, maybe a detailed chart, maybe a PCB schematic, whatever.
These people, being considerate of their readers, want to ensure if someone with a 13" screen comes along, they'll get scrollbars or small text, rather than a badly reflowed table where the word 'Yes' gets split over 3 lines.
Other people want to read those documents on 5" phone displays.
Some people write documents that can only be clearly presented on a 15" or larger display. Maybe a comparison table with a bunch of columns, maybe a detailed chart, maybe a PCB schematic, whatever.
These people, being considerate of their readers, want to ensure if someone with a 13" screen comes along, they'll get scrollbars or small text, rather than a badly reflowed table where the word 'Yes' gets split over 3 lines.
Other people want to read those documents on 5" phone displays.