I imagine plate armor is uncomfortable as fuck... Capes are dope though, but I can imagine them getting caught in various things causing fatal accidents (escalators, revolving doors, moving trains, etc.)
Its not difficult to engineer a bit of safety into a cape. The clasps holding the cape around your neck/on your body can be designed to have a low breakaway strength to prevent strangulation(150N is a typical force). This is a feature designed into most safety helmets. Its secure enough to never fall off unintentionally, but weak enough that it removes the risk of strangulation.
This is literally what capes were like. The world was even more dangerous back then and the human brain hasn't received any upgrades since capes went out of fashion :)
Yeah, both Zendaya's costume and C3PO (and many other robots in sci-fi) have the Metropolis aesthetic.
Just that Star Wars being as popular as it is means C3PO is iconic on his own, and no one thinks a lot about why the stylistic choices were made when they designed the C3PO costume in the 70s.
It was exactly a metropolis inspired look. She got it out of a museum basically. It was on the runway in the 90s(?) as an homage to the robot woman from Metropolis.