Depends, my oldest girl has a coat and boots; she's a shorthair, ice can be sharp, and -30C is fucking cold.
Anyone who thinks that's silly can come here in the winter, strip down, then run out in the yard to shit.
As for decorative clothes, whatever. If the dog doesn't mind, neither do I.
I like putting some clothes on my dogs because it's funny and kinda cute. My male dog is used to it and doesn't care.
I will put a scarf on them during cold winter days.. They don't need it but I cannot resist.