Ummm...well...

They don't seem like a particularly good idea to me, but I'm not a woman. Wouldn't it be better for the health of one's breasts to simply wear a sort of soft inner cloth shirt which covered the breasts but didn't restrict them so much? I don't know what you'd call it, but it sounds like a better idea than encasing yourself in Zena-type armour, if you know what I mean. Anything that constricts a body area and reduces blood flow to the tissues can potentially cause health problems. Restricting air flow to the body can also cause health problems.