@Brizzlemint do you not think museums and hospitals make a difference?
A family friend's a designer. Used to design interiors for shops and restaurants, and then moved into museum design. Won awards for designing various exhibitions as a freelancer at places like the British Museum and V&A. His skill set didn't seem any different to an architect's, to me. He did a lot of technical drawing and complex calculations. He made spaces look beautiful, and function better. That's what a good interior designer does.
Teachers and doctors and nurses benefit from good interior design all the time. And suffer, as well, for lack of it. And unless you've never enjoyed a meal out, stayed in a hotel, used an airport, or museum, or bought anything in a shop, you can't really say you've never benefited from their skills there, either.