Journaling is not a spiritual practice in itself, but it is used by people who are on a spiritual journey. Journaling is used by many all over the world, regardless of their spirituality, religion, age, or gender.
I have met many spiritual people who use journaling as a tool for clarity and for understanding themselves along their path.
The path people are on is not always straight forward or easy. People lose sight of their path and lose clarity about where their path is leading to. They discover many difficulties and struggles along the way.
They use journaling as a tool to correct themselves when needed, to understand if their ways were true to who they are or not. They use journaling to understand themselves and who they are better, and to keep learning about themselves as they go down their path and evolve.