I was lucky enough to be flown to Rome first class (on someone else's dime). Delta out, United back.
Each airline gave us a little overnight kit: Sleep mask, socks, toiletries, etc.
Compare the nice reusable case that Delta provided to United's nylon sack. Delta probably spent at most $1 extra.
But the experience and perception of quality is radically different.
Details matter. Save money behind the scenes — never cheapen the customer experience.