My experience: intuitive thinking it's a shortcut, but it's less reliable when it comes to complex problems, especially involving multiple concepts that have to be reasoned about with non trivial relationships or rules. In a way I see a spectrum of approaches that range from fast to reliable:

1. Intuitive thinking

2. Language based internal monologue

3. Written scratchpad

4. Explaining the problem to another person until they understand it (rubber ducking)