Are text property mixins a good idea?

Question

css

Is it good practice using preprocessors to write something like

mixin text-xl-heading
  font: italic bold 7.2em/.75em 'Helvetica Neue', sans-serif
mixin text-md-heading
  font: italic 2.2em/.75em 'Open Sans', sans-serif
mixin text-plain
  font: 1.4em/.75em 'Open Sans', sans-serif

Usage

h1.main-heading, span.important
  +text-xl-heading
h2.sub-heading, span.interesting, blockquote, a.link-inner
  +text-md-heading
p, a.link-outer, span
  +text-plain