I've told a couple of people at work I feel comfortable with about my diagnosis. And once I do, I get the "I wouldn't have known if you didn't tell me" response. So I think if you're stable, it's not even noticeable, I think it becomes an issue when the depression sinks in, because that can be harder to hide than the hypomania I experience. Luckily my hypomanic episodes don't include irritability so much thanks to my mood stabilizer (at least I think that's what's going on).
I think what keeps the stigma going is that when there is some mass shooting, it's usually mentioned afterward that the person has some sort of "mental issue" and it makes it seem like people with MI are violent when in fact we are not.

Edit: I do consider myself successful in my career, I've bought my own house, have a good job, have a nice car etc.. all on my own