My wife is riding a 50mm stem. Here is why she is riding it.

My son is a long body. So as he grew, we had a nice racing bike with too long a top tube for a normal fit for her, but, didn't want to waste it and some nostalgia there.

She also likes a low TT position from years of riding that way. So it has clip-on aero bar short extensions. The handling is slightly better on extensions with a shorter stem. So...we go with it.

It kinda looks bad, works well.