In “I Wandered Lonely as a Cloud,” explain Wordsworth’s argument for the value of beauty.

I'm not entirely sure that Wordsworth is making such an argument. Rather what he's doing is to show us the remarkable effect that nature—not necessarily the beauties of nature—can have upon the creative faculties.
It is, after all, the host of golden daffodils that puts a stop to the speaker's creative wanderings and fires up his poetic imagination. Yes, the daffodils are undoubtedly beautiful, but it's not their beauty that inspires the poet so much as the remarkable order they display as they flutter and dance as one in the breeze. Such order and unity could just as easily be demonstrated by a dark forest or a high mountain, or a storm-tossed sea, all of which could be described as awe-inspiring rather than beautiful.
What matters for Wordsworth is that the features of the natural world should show themselves as part of a unified whole, a gigantic cosmic unity of which everything in the universe is a part, including humanity. If they do, then they will, like the host of golden daffodils, spark the poet's imagination into life and enable him to create.
https://www.poetryfoundation.org/poems/45521/i-wandered-lonely-as-a-cloud