grammar - Using "a/an" twice describing "one person"

Is it grammatically correct to use an indefinite article "a" twice in the following sentence:

Sean is a coward and a psychopath.

There is a previous question about a definite article the, "Is it necessary to use “the” multiple times?", but it doesn't seem to answer my question.

Answer

Who says (said) there is (was) an error? Sounds pretty OK to me.

With more words and perhaps a bit more force, you could say,

Sean is both a coward and a psychopath.

Or,

Sean is at the same time a coward and a psychopath.

Or,

Sean is a cowardly psychopath.

Or,

Sean is, at the same time, a coward and a psychopath.

Or,

Sean is characterized by cowardice and psychopathology [in the sense of abnormal, maladaptive behavior or mental activity.

Or,

Sean is an odd mixture of cowardice and psychopathology.

Or,

I would characterize Sean as a cowardly psychopath.