[QUESTION]

Because he is naked.

Okay, let's look at this not from the perspective of practicality, but from the perspective of logic. Is such an outfit logical for this character?

The elbow area is exposed, which is easily vulnerable to a sword, and the shoulders, where a sword can hit even accidentally. The chest is exposed; if a sword gets through, death will be quick.

Not the lightest version of Roman armor. Nevertheless, the elbow area, as well as the legs, are exposed. Even if you put a woman in this armor, you can again say that the author was only thinking about showing off the character's seductive legs. And in general, at that time, many soldiers wore clothes that covered far from all parts of the body. But why? After all, their creators weren't thinking about the curves of the soldiers, were they?