In this simplified case probably not you're right. But it guards against the more complicated ones, for example our form has two labels (one called a legend goes underneath the control):

  <fieldset class="TextField">
    <label class="TextField-label"></label>
    <input class="TextField-control">
    <label class="TextField-legend"></label>
  </fieldset>

Just makes it future-proof for when you want to add other elements that might collide since the number of element types is small.

Generally I try to never select on non-class selectors in component-level CSS. Component-level styles should occupy the middle range of class selectors. And then the user should have control over the element selectors (base styles) and id selectors (page-specific styles) so that they can both cascade and override when they need to.