I am using a color wheel to set the color of a material instance and at the same time in the UI (UMG) show a preview of what that color would be. It worked fine for the actual mesh but didn't really work right for the image, it was flipping to certain colors and didn't interpolate nicely. Just now I looked at some older UI blueprint code and noticed that I had wrapped the image in a border and mistakenly set the Content Color and Opacity to 255, 255, 255 instead of 1, 1, 1 which are the correct numbers. The rest of my UI actually used 1, 1, 1 everywhere because I had learned at that point that the expected value is a float from 0 to 1 (for example using a slider to set a color will do this automatically). But I didn't know this at the start, if I know that I wouldn't have typed 255, 255, 255 and spent a day scratching my head at some weird behavior.

The Content Color and Opacity node takes a struct, but when you split it (which I did) it shows In Content Color And Opacity R, G and B. Normally when I think about RGB colors I think in numbers like 255, 255, 255, so having the actual expected values shown when hovering the float value would be helpful. Or maybe as an alternative a warning shown in the compiler results when you're using values that are not in the expected value range.