Yes. I’ve thought about this, and how I might justify it if I were to use it in a story.

Consider. Magic is powerful and somewhat common. And we’ve already seen in history examples of aesthetic fashion taking on the lines of real armor.

The doublet was made to mimic the lines of armor.

It seems plausible to me, that you may have a society arise in which wealthy second and third sons must go adventuring for lack of inheritance, and perhaps even uppity daughters that don’t want to be brood-mares for dukes. Now, the common folk would get by on regular steel armor.

But the wealthy? Nothing so mundane. Why should not a lordling have crafted for himself comfortable, fashionable clothing mimicking the lines of armor, but relying on magic for actual protection?

A set of comfortable spelled greeves, a magic helmet, and suddenly this actually works.

As this becomes more common, it may become more extreme. A few garments to evoke armor, or even dispense with the pretext alltogether. The less you wear adventuring becomes a way of advertising wealth.

German landsknecht used to advertise their skill by peacocking with bright colors and wasteful slashed cloth.

“Behold, I am so skilled I can afford to be this wasteful of fabric!”

So too our magical society follows, but instead of dye and cloth they waste magic to advertise their wealth. Rather than wearing heavy, uncomfortable plate, adventurers peacock with less is more.

Behold a poor, unskilled knight, who must rely on heavy, hot, uncomfortable steel to see her safely through.

Compare with…

“See how rich I am? I can afford magic so powerful that this mere trinket offers me more protection from steel, tooth, or the elements than your plate harness!”

And that, ladies and gentlemen, is how you justify bikini armor. Contrive a context where it actually makes sense.

For more, read Quill and Ink

Original question-Is there an in-universe way of justifying bikini armor? It seems so impractical.