Persona Poems: a useful term or a red herring?

I came across this term for the first time the other day and immediately understood what it meant. In other words, it must be a useful label for teachers and tutors as shorthand to refer to poems deliberately written in a voice that’s separate from the poet’s own identity.

However, on reflection, I found myself picking the term apart. All poems, whether their creators like it or not, are persona poems to a greater or lesser extent. In supposedly autobiographical pieces, how much of a persona is projected, either intentionally or unintentionally? And in explicit persona poems, how much or how little of the poet is implicated and involved in their character?

In fact, I’d go as far as stating that a considerable chunk of the genre’s interest lies in the tension that this above-mentioned ambiguity generates. The so-called lyric “I” can be deliciously undermined to great effect…!