I'm 5'9", and rarely have a problem with the person in front of my reclining, but I can absolutely see how it could create comfort issues for taller people.

It is more difficult to use a laptop on a tray table if the person in front of you is reclining; you often end up having to angle the screen down to the point where it's not great. In that case I often have to ditch the tray table and put it on my lap, which is less comfortable, but at least lets me angle the screen how I prefer.