TiddlyWiki and Regular Expressions go together like a hand in a glove. The core parsers use them extensively.
RegEx is one of the few things I understand. They are not exactly precise coding. They are more like crossword puzzles. You looking in "match" to capture ALL but ONLY.
But a lot of confusion for beginners arises in that Regex are Context Dependent. There is NO perfect Regular Expression. Say it again: There is NO perfect Regular Expression. Its a pragmatic tool, not a perfect one.
So its very important to test your use case with example data first.
With those caveats ... RegEx does things really well. Its likely the most useful tool for preparing stuff and for tidying up.
An aside
Josiah