Dynamic Type in iOS for interactive elements
<p>I am currently implementing an iOS application with support for dynamic font sizes (for accessibility). I read Apple's documentation on the matter[1], and it states the following:</p>

<blockquote>
  <p>The fonts returned using text style constants are meant to be used for
  all text in an app other than text in user interface elements, such as
  buttons, bars, and labels.</p>
</blockquote>

<p>Why is that? Wouldn't it be particularly important to adjust elements such as buttons in an application, since those are the parts where the user interacts with the application? This becomes even worse when the user sets the dynamic type font size to something very large, because elements like buttons are even harder to see because everything else becomes so much bigger, but buttons stay at their 15pt font size.</p>

<p>I am interested in: What is the reasoning behind this? Should elements like buttons just stay at their default font size, how do others handle this?
Also, I am unclear on what exactly is supposed to be dynamic and what isn't - how about textfields, the label of a textfield or explanatory text (which is a label)?</p>

<p>[1] <a href="https://developer.apple.com/library/content/documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/CustomTextProcessing/CustomTextProcessing.html" rel="nofollow noreferrer">https://developer.apple.com/library/content/documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/CustomTextProcessing/CustomTextProcessing.html</a></p>