Yes and no. A wall painted a different color for no apparent reason has had its day, but a wall painted to showcase a piece of artwork, or for drama that works with other things in the space, or just for a pop of another color, is still being used. However, it should not be the main wall in the space. See Houzz photos under "contrast walls" to see what I mean.

These days, pops of color are likely added in accessories, pillows, throws. Personally, I prefer the term "accent" wall and i usually like them to be unpierced by windows or doors. I do make an exception for a fireplace wall, but since yours also has a window, I don't think that is the wall I'd paint.