If I am looking to make a business selling 3d models, 3d Selfies, 3d customized printed parts for example; iphone holders, keychains and that kind of stuff. Will my eyes be able to see any difference in the result if I buy a printer with 20 microns resolutions vs 100 microns resolution?

I heard that a human hair is about 45-75 microns, so I doubt that I can see any diff