[2038AD]

It's simple and easier to read.

A slightly lower contrast may look nicer (and be more accurate to printed text) but often sites are excessive with it. It may not even be exactly the designer's fault since their monitor's gamma and contrast will probably be better than the average visitor.

Another related problem is that of font weight. Fonts too thin can also hamper readability but the weight on-screen will be variable with the user's font settings and how exactly it's set up with aliasing, shaping etc. To add to that some digital fonts are displayed at the wrong weight because they were designed with bleed in mind.