title: why not just use sp for everything instead of dp?
body: <p>While defining a view in android, we use dp for margins, sizes, etc but for text sizes we use sp. sp is also same as dp but for texts. Why can't we use sp for everything then?
  <strong>I know the difference in between the two. I am asking if sp is a superset of dp, why use dp at all? why not use sp to specifiy all sizes in views?</strong></p>