Well, different poems offer different pleasures, to different readers, in different ways. Which might be sufficient if you're not an academic forced to justify your salary. I've quoted Bunting on the Poet and Politics before, and I think he was right. So here's Browning on one value and pleasure of a type of poem.....It comes at the end of The Ring and the Book, where Browning has performed his argument:
Why take the artistic way to prove so much?
Because, it is the glory and good of art,
That art remains the one way possible
Of speaking truths, to mouths like mine, at least.
How look a brother in the face and say
‘Thy right is wrong, eyes has thou yet art blind
thine ears are stuffed and stopped, despite their length,
‘And, oh, the foolishness thou countest faith’
Say this as silvery as tongue can troll-
The anger of the man may be endured,
The shrug, the disappointed eye of him,
Are not so bad to bear-but here’s the plague
That all this trouble comes of telling truth
Which truth, by when it reaches him, looks false,
Seems to be just the thing it would supplant
Nor recognizable by whom it left-
while falsehood would have done the work of truth.
But Art—wherein men nowise speaks to men,
Only to mankind-Art may tell a truth
Obliquely, do the thing shall breed the thought,
Nor wrong the thought, missing the mediate word.
I like that said Offa. Sing it again.