It's affected. Not trying to say do it or not do it, but don't pretend you're being a traditionalist by wearing them, because traditionally they were never to be seen. So you're into 'quirky' territory.
Your pants sit differently wearing them. Less squished in like a belt does, but less low rise than is popular. While suits should be sagged like jeans, even they are not worn as high as they were in years past.
Just don't wear a goddamn belt with your suspenders and I won't cringe too bad even if they're a weird look.