Paint is subject to the effects of radiance. How paint looks changes depending on the surrounding lighting in the room, including the colors of other walls and objects which the light bounces off. So even if you could pick out a color from a perfectly calibrated display, then look at it under ideal white light and see that it matches, it won't look the same when painted on actual walls.
Don't downrate, (s)he's right. If you are going to paint something, paint a sample foamboard or something and view it in the right context. It is remarkable how the color of paint can be affected by its surroundings as it refracts and reflects. It will look rather unlike the pictures in the catalog if your lighting conditions are different.
With most paints, the medium used can affect color, as well as aging. I used to use Ph Martin watercolor dyes, and they were notorious for fading after a relatively short time. The illustrations that I colored with them, are now monochrome. I’m sure they’re better, now. Pigment science has come a long way. Acrylic was always a lot longer-lasting.
Also, context matters. Our perception changes, based on surrounding colors. There’s a bunch of optical illusions that leverage this.
