At the moment https links to external sites stay as links, and don’t display any dynamic preview. Having previews of external links is extremely useful both from an at a glace pov, but also to get more general information about what it is you are looking at.
Additionally for internal links as In the case of OneBox in discourse, you could even use link previewing to expand and display other notes inside the current note. This becomes an entirely new way of navigating information whilst keeping explicit context - something that clicking through and opening a new note can’t do.
I appreciate these would probably need to be ported:
It would be great if Obsidian had an option to enable OneBox on http links in the same way that discourse does (as seen in this forum).
There is also another example of link previewing in Signal Messenger which I believe is more privacy focused: