Spectate as an item frame, lead knot or painting

When in spectator mode, you can click on entities and look at what they are seeing, so I thought, what if you click on a painting or item frame because they are entities too. So I did, and you are able to "view" what the item frame or painting is seeing. I also tried it with some other things such as fireballs, arrows, and flying wither heads, but it only seems to effect item frames and paintings.

P.S. I did not find any other reported glitch explaining this, so if I am mistaken and there is already one, sorry...