When opening a page in Link Preview, make it available to extensions so that, for example, 1Password works. Even after opening the Link Preview page in a proper tab, 1Password was not usable at all from that tab. I had to reload the page to get the 1Password auto-fill UI to show and be able to login to the site in question.
I've now several times found myself wanting to use 1Password to directly login to a page opened in a Link Preview, but was unable to because 1Password did not know the page existed. I imagine this might be an issue for other auto-fill or similar extensions which work with page content. For example, folks using custom ad-block or privacy extensions might be unhappy to learn their extensions don't work in a Link Preview page.