Remove extends

Articles like http://www.sitepoint.com/avoid-sass-extend/ and http://csswizardry.com/2014/11/when-to-use-extend-when-to-use-a-mixin/ explain why we should only be using the Bourbon mixin instead of extends for clearfix and hide-text. I felt the separation for buttons was superfluous. 
Should we use Bourbon’s helper here (`#{$all-button-inputs}`)?