Currently, you can turn a search portal into an embedded queue, but you can only go back to a normal portal, losing both the search criteria and the auto-updating of simple search portals.
I’d like to have embedded queues that, e.g., always have the cards that I tagged with #learn, without having to re-create the search portal manually every time.
(When/if a query system comes out, it will be interesting to recover the query and not just have it auto-update.)