That "normal viewing distance" mantra is a simply an excuse for sloppy work. I often make big print, and people put their noses right into them.
That's what they do when you give them that choice. They discover details, and that's part of the richness of the print that just keeps giving
over time. A totally different thing than merely grabbing your attention real fast ... which is the objective of advertising photography and, alas,
much that claim to be art these days. If you want a rich big print, you need a big camera, preferably an 8x10. I love 35mm photography too.
But making a big print from a negative the size of a postage stamp is about equivalent to creating gang graffitti with an aerosol can. It's all
basically a wad of fuzz.
You don't need a big camera to make large prints. When did we all start assuming visible grain is a bad thing ? Grain is often very beautiful and adds to the richness of a print.