The only real benefit I get from the Readwise integration is that it automates it. And if I didn’t automate it, I would NEVER remember to export my Kindle highlights.
And once it is automated, the text is there to be searched and processed. And it includes links back to the passage, so I can jump straight back into the Kindle app to find the position in the book, if I need more information.
I do occasionally read random highlights on the Readwise website.
Even with the integration, I still manually curate my book notes after they are collected by Readwise. (I roughly follow Tiago Forte’s “progressive summarization”.) And I still store separate atomic quotes in my “Commonplace Book” when a core idea strikes me. That is a separate folder in Obsidian, but I am considering staying in physical index cards.