“The difference between fine art and decor comes down to intent and purpose: fine art is created for emotional and intellectual expression, while decor is designed primarily to complement an interior space and match prevailing aesthetic trends.” ~Milan Art Institute
https://www.milanartinstitute.com/blog/the-difference-between-fine-art-and-decorative-art
My Thoughts:
Fine Art gives one an emotional experience, like when you go to an opera and start to cry. On the other the other hand, decor is more like stuff to fill in some empty space, like when you get on an elevator to listen to the music.
There is no expert who can say, “This is Fine Art and that is Decor.” Beauty is in the eye of the beholder so each person can make up their own mind, but to me, one indication is how much talent and skill does the artist actually have? If the artist is poorly trained and posses little or no skills, then most likely it will be decor.