This experiment was made to research the feasibility of re-building our search from the ground up and what are the trade-offs of this new approach. While it’s too early to tell, if the new search experience is received well enough it can then be considered to be integrated into Discourse many search features, be it full page search, inline header search, similar topic search for Related Topics, user mentions, hashtag autocompletion, etc.
That’s easily doable with this technology, both on mobile and on desktop, much like Google search UI.
Modes only exist for the experiment so people are able to easily compare and test, if this were to ship modes would become an admin option most likely, instead of something user facing.