In TiddlyWiki wikitext it does cause problems, that’s why if you use whitespace for indented macro code you should use the \whitespace trim
pragma. eg:
The right way to do it for TW core code is the second example
\define button-text-01()
<$let a=1 b=2>
<$button>some text</$button> some more text
</$let>
\end
\define button-text-02()
\whitespace trim
<$let a=1 b=2>
<$button class="tc-tiny-gap-right">some text</$button> some more text
</$let>
\end
<<button-text-01>>
<<button-text-02>>
While the visual HTML output is the same, the HTML code is different. The first paragraph can create all sort of subtle copy paste problems if used in the TW UI
<p>
<button class="">some text</button> some more text</p><p><button class="tc-tiny-gap-right">some text</button>some more text</p>