A wise girl knows her limits.
A great girl knows she has none.

Could playing with cross dressing be healthy and why?
Cross dressing could make one more open minded about expressing oneself in different ways, but I don't think it's necessarily healthy or unhealthy to do it. Some people are comfortable being their own male/female selves, and others find cross dressing a fun activity. The benefits really depend on each individual, in my opinion.

Is cross dressing more difficult for boys or girls and why?
It seems like it's more difficult (but also more fun) for guys to dress as girls. We always see girls wearing pants and loose tee shirts, but it's really quite a sight to see a man in a skirt and close fitting clothes. So to see a girl cross dressing, it's not as surprising because it's not that much different from what many girls usually wear. We also see more "tomboys" than feminine boys.

Can gender binaries be blurred? And if so, what are the consequences?
It can be, and it is being blurred. I don't think there are any men than don't have even a little bit of femininity, and girls that don't have the least bit of masculinity. Maybe it's subconscious, but it's definitely there, and if encouraged by certain situations (like cross dressing) it becomes easier to blur that line between the male and female sexes. Since it's happening right now, the consequences can be seen anywhere and everywhere, but on a larger scale, people might not accept it or be comfortable with it at first. But people now, especially the younger generation, are becoming increasingly open minded and things like these are acceptable and no big news.