Why not define font-weight or font-style in @font-face, Font Squirrel?

Question

When we define @font-face styles, we can define whether the referenced files are for the bold, italic, or bold italic versions of a font, as discussed in this SO question:

Answer 1

By default, Font-Squirrel does this in order to increase support with user-agents that do not follow specification (those that ignore font-weight and font-style).

If you do not care about those outdated user-agents, you may enable the "Style Linking" option which is available in the expert section of the @font-face kit generator. Note that IE8 and below ignores numbered font-weight values and only support normal and bold (and corresponding 400, 700 weight values).