That is indeed simpler, but not nearly as powerful or as flexible.
As far as I know, no default Firefox setting will allow you to impose different font sizes per website. Also, the setting you mention will change only the font size, and not the zoom level as a whole (NoSquint can change either).
Finally, the setting you mention does not affect font colors or background colors, as the Stylish stylesheet does.
As far as I know, no default Firefox setting will allow you to impose different font sizes per website. Also, the setting you mention will change only the font size, and not the zoom level as a whole (NoSquint can change either).
Finally, the setting you mention does not affect font colors or background colors, as the Stylish stylesheet does.