Should my pattern editor key typically match my project key?

Cubase
1

Say I’m writing a song in F Phrygian. I set the pattern editor to F Phrygian. Since F Phrygian is based on the Db major scale, should I set my project key to C#?

As a separate but related question, what is the importance of setting the project key rather than leaving at empty, i.e., as the “-” option? Based on the documentation, it looks like this feature is mainly used to transpose events. If I don’t plan to transpose anything, perhaps I should just leave it blank?

2

This is the correct conclusion.

The feature is great for example if you have a vocal talent who would like to have the whole project in a different key in order to fit their vocal range better.

3

Thank you!