Combinators are much more flexible and powerful then parser generators such as leex/yeecc described above. Due to we have the functional language with pattern matching, the use of them becomes yet more yummy. Another very important advantage is the ability to parse arbitrary binary data (with bitfields), not only text.
Saša Jurić - Parsing from first principles - WebCamp Zagreb 2019
Parser Combinators are also very important in the case of writing binary parsers: file readers, network protocol dissectors, etc. So, you must know this powerful technique and has it in your toolbox as a skilled Elixir programmer.