Modern LCD displays can display very high resolution. But instead of using it to improve readibility, I typically use it to squeeze even more information on a single display. Writing a text using different sources fills up my screen with multiple windows.
But… become older my eyesight is degrading slowly, so I need larger fonts to keep things readable. With Microsoft’s ClearType tuner I have improved readibility significantly, with the same font. It works especially good LCD displays since they have less “smudge” than CRT displays.