This option was deprecated in later versions, and now the search suggestions settings for both bars are linked, whether unified or separate. In older versions of Firefox, it was possible to disable search suggestions separately for each of the bars.
While these suggestions may be useful for some, you may want to disable them for various reasons e.g. The suggestions may be fetched from any of the following sources:
Firefox still shows suggestions whenever you start typing anything in either bars. Now, beside this change, the behavior of the bars hasn’t changed that much. Nevertheless, in the Search Settings one has the option to enable the classic separate bars. This however changed with Firefox 57 (Quantum) which introduced the option for a unified bar that combines the address and search bar into one. The classic Firefox desktop browser had by default a separate address bar for navigation and a search bar for search.
