Would you use the same word to imply 'very skinny ' when talking about a person, as it is in English? Such as 'este homem é fino' for 'this man is thin'
I would say "magro" or skinny. For some reason "ele está fino" just sounds funny to me.
Ele está magro. Ela está magra.
Yeah, it is also another possible option. They might include it soon.
There is actually a difference, and it applies here when talking about "thin" curtains because drapes are usually lined, pleated, and hang from above the window on a rail, track, or rod to the floor. You can even have a curtain under the drapes so that the light can come in but maintain some privacy even with the drapes open.
In Portugal they tend to use persianas which are usually metal blinds/shutters that are actually on the outside but controlled from inside either with a manual strap (frequently malfunctioning) or electrically. I really dislike them as they are pretty ugly, very noisy, and turn the home into a cave, but it could be good for getting sleep (and sleeping till noon) cause they do effectively block light. They apparently can add to security some as well and when it is very hot help keep the heat out (but do not seem effective in keeping heat in):
Anyway, I would describe curtains as thin and drapes as fine (fancy, luxurious) which would cover both meanings of finas (fino, despite the Duo hints only allow for thin).
In practice though it seems Portuguese usually calls both cortinas.
And of course drapes can be worn, or threadbare due to an insect infestation.
Indeed, it can be used this way. The word "fino" may present a "thin" meaning or a "fancy" meaning. "High quality" would fit in the "fancy" meaning.