Batman's cape is VERY much a functional tool. Not just in terms of gliding and cover, but in completing his intimidating image, which is one of the biggest tools in his belt.
None of those things outweigh the fact that a cape is a hazard that can get stuck or get grabbed in a fight.
Superman's cape is often justified, as it was in MOS, and similar to how much of his suit is justified, by the fashion and customs of Krypton. 'Hope' anyone?
Yes, and I'm totally fine with that cape being part of Kryptonian fashion, but that still does not make it practical.
Also I really dislike the chest emblem literally meaning 'Hope'.
Now, that said, the exact same could have been used to justify the trunks for Kal, especially in MOS.
First off, speaking in MOS specifically now, Kal's suit is centuries removed from "modern" Krypton, coming from the ancient scout ship. This is emphasized/showcased in the colours. Superman's suit has more colour than all other modern Kryptoinian's put together, lol.
Modern Kryptonians clothes are all but monochromatic.
Tell that to the people who think the Jor-EL AI made the suit at the same time he was talking to Clark.






)
