I can speak to both sides.
Yes, yes, yes. What you wear and how you wear it are super important. It is taken incredibly seriously because you're supposed to take the tournament seriously. I learned so much about grooming and ironing from speech and debate.
I only did Parli (the most worthwhile of debate styles) and I have to be honest, it's definitely tough for females. I can't count the number of times my partner and I would be told by our opponents that we were just taking X topic too personally to be unbiased about. Even topics that had nothing to do with either of us. We lost the gold round in nats because two of the judges thought we were taking the ICE topic too personally, "perhaps because we had family effected by it" according to one judge. Neither of us have ever had anything to do with ICE. . And there's a huge gender bias in that debate tends to be predominantly male. My partner ultimately got more shit for being "emotional" and "illogical" than I did, I think because I had super short hair and wore suits so everyone assumed I was a trans dude.
For anyone who wants to go into interp or platform, take your coach's suggestions seriously but do not let them bully you into doing something you don't want to do. My first year I let my coach convince me to do a piece about a trans dude getting a fucking bike because I was rocking short hair. I did not give one flying rats ass about that fucking bike. I could not sell it. This is barely related to anything helpful at this point, I'm just going to be raging about that stupid fucking Schwinn bike to my dying day. Fuck you, Schwinn, and your shitty fucking bullshit bikes.