"This has a coat."
Translation:Αυτό έχει ένα παλτό.
I guess the unnatural "This has a coat" is originated from the Greek original sentence where they started from: αυτό in Greek is neuter, but they have plenty of human beings who can be (grammatically) neuter: Το παιδί, Το κορίτσι, το αγόρι, το άτομο, so it could be "the child or the boy has (got) a coat, for instance. But, whenever in Duolingo αυτό is found they translate it with "this", which in this case it sounds quite strange indeed.
Ah, but if you check out the comments
you'll find a number of logical uses for this expression.
Also, remember we are teaching vocabulary and syntax to make you able to create your own sentences. We have thousands of sentences so if not all of them are literary masterpieces...well, at least they are eye-catching.
There are whole sites on the net Reddit, youtube, twitter, etc with examples of odd Duolingo sentences.
Are you learning vocabulary? I hope so. Are you learning the correct syntax? Again we hope so.
Do you still have 70 Skills to learn many more useful sentences? Indeed you do.