My mundane little brain put it in a shop window or clothing catalog. No, it's not an expression I'd use every day but it's not as odd as you seem to find it. Sentences without context can be confusing but just take them as linguistic Rorschach tests and look for the butterfly in each.
It only sounds strange in English, because in English pronoun "it" is usually not used for sentient beings. But remember that in Greek (as well as in a lot of other languages) words like "child", "boy", "girl" etc are all neutral.
'This' or 'It' has a coat? hahaha... What is 'this' or 'it', a dog, a mouse, a cat? What could be 'this' or 'it', having a coat?
First of all let me point out that we are trying to teach vocabulary and syntax to give you the ability to create your own sentences. Many of the sentences on Duo are without context so might not seem to be practical.
My thought on this sentence was that we are looking for a coat and found one in a mail-order catalog. So, "this catalog has a coat." or I have been to various stores and "I went to Macy's and it has a coat." But I'd agree with you about the animals...at least I've seen dogs with coats.