Is it appropriate to include a talk one has given into an application to show familiarity with a certain topic? Is it appropriate to include a talk one has given into an application to show familiarity with a certain topic?

For example, if a possible future employer demands some knowledge about a certain topic, would it be appropriate to include a seminar talk I once  gave about that topic into the application? Or would that be considered inappropriate or unnecessary?

Assume that I don't have published any papers about that topic yet or taken any graded courses.
I think that it is perfectly fine to include something like "Prepared and presented a lecture/talk regarding {subject}" in either your motivation letter or your cv or in both.