How does it make you look better?
It doesn't really, except to yourself.
The numbers will look bigger (so "better") when you look at them, but when anybody else looks at them, they will be shown in that user's units, not yours.
I now have my Wahoo set to show distances/speeds in KM, but have Strava set to miles. But that is partyly so I don't have to convert in my head to know how close I am to another Lunacy Challenge ride (my target current;y being 60Km).