They did definitely cover up more skin, but a single boob plate and some random pauldrons doesn’t actually seem that much better in terms of actual protection. Most of it’s just fabric
I have to admit that it's the kind of armor that I would normally criticize (boob plate especially) but being part armor/part fabric is exactly what I would expect for a half martial/half magic class, so I think it holds up well enough. Plus the guy that kicked her out of the party was just wearing leather over even less of his body, so she's at least more protected than him.
If I were to try justifying it in lore I would say "it's enchanted with powerful defensive magic so it doesn't matter what material it's made of" but criticizing the use of in-universe lore as justification for the author to put characters in impractical clothing (or exercising any other fetishes they may have) is kinda the entire point of this story, so this armor does seem a little hypocritical lol