one aspect of my proposal was to not make any web requests until the user requested them.
That increases privacy when sharing links by making the preview opt-in.
It’s not a given that always you want those previews, for sites like GitHub they are boring and not always helpful, so in the messengers with link previews I quite often need to remove the embeds/previews. Although I want to have them for social media, blogs, youtube and audio streaming platforms.
EDIT: this was my personal opinion, after internal discussion opt out is a better default for most users though we could do a setting to disable fetching previews for the people that have one of the rare special use cases where they want to send a link without making the web request to fetch the preview.