Yes to all the reasons mentioned above!
I love originality, wearing things that nobody else has. I love "dressing up" for occasions - and there's nothing better than vintage for that. I love the glamour of by-gone eras, yes, and wearing something from such a time gives me the feeling to have a little bit of that glamour. And vintage clothing is often so flattering, I shop a lot at thrifts, charity secondhand shops and such. Not everything I find there is strictly speaking vintage, but it's often not expensive. Thus, my money contributes to a charity (and usually these shops also employ people who wouldn't find a job otherwise) and I have rescued a garment from being thrown away, when it was still good enough to wear. I don't like the idea of buying cheap stuff that will disintegrate after five times wearing or isn't even lined and will show everything that I'm wearing underneath. Or the idea that it was made under appalling conditions. I also like natural fibers better - cotton, silk, cashmere, wool... and there are great, affordable vintage clothes out there made from these. Yes, of course there's vintage synthetics too, but then a gorgeous 1940s crepe will beat any modern polyester or whatever. For winter I favor high-heeled 70 Italian leather boots - they are the most comfortable high-heeled boots ever, and they are elegant and almost indestructible. I also love colors, and unusual colors, which one finds more easily in vintage things.
I absolutely hate modern inexpensive business wear - and I see that a lot in my job. Instead, I wear vintage suits, dresses and separates, mixed with modern high-quality things (bought secondhand - my clothing budget isn't that big), when events call for "business wear". I would rather wear something nice that doesn't look crumpled after half a day at a trade show, and I don't want to add to the general boring mix of black and grey either. I always make sure I wear something that adds a splash of color.