Had this debate when we bought monitors for the firm. Some in management said high DPI, good color etc. are not worth the money (which you clarify is what your really mean). But after splurging, the effect on productivity was measurable. If you pay someone to stare at a box for 8h, a nicer box pays for itself pretty quickly.

Personally I don’t mind a small UI so I currently just run (macOS) on 3840 × 2160 on two 24” LGs. With size 11 Fira this gives me 8 80char columns.