i used it at my last company to differentiate between similar file type documents. For example, some excel files were category=Cost Estimate, and some were category=misc.
I "THINK" that once you set the category you can't change it, but I'm not sure.
I'm now using a variable called doctype which can serve a similar purpose, but is a little more flexible.
Yes, it's true that Categories can never be changed for a file once it's set.
I also have opted for using a variable to differentiate between document types as well as other properties, such as approval paths, life cycle phases, etc. I also like the fact that with variables you can create as many kinds of categorizations as you want to more completely specify/identify/track a file. With categories, each file can belong to only one.
But you dont have to use categories in the workflow as long as you use the built in conditions.
Here I check the datacard to make sure that all the variables are not empty (!="").
Check that the first letter in the number isen't 0abcdefg..... [^ 0abcdefghijklmnopqrstuvwxyzæøå-]%.
Check the file path is not \\Prosjekt\21440\ (!=\Prosjekt\21440\%).