That depends on whether you give a rip about what other people think of you.
I have found that the older I get, the less other people's opinions of my appearance matter to me. For me, it's function over form.
I would never wear a 3/4 helmet or fingerless gloves under any circumstances on any bike because they would not protect me adequately.
Perhaps another question is in order: Is the rider who purchases, say, a Thruxton R (drool) doing it for appearance, or for functional reasons? If appearance, then it makes sense to go all fashionista on it.
The attached photo is on my wall at work. Full Pilot leathers, blingy Arai, gauntlets... on a Thruxton. I don't think it looks silly.