You mean like being able to read the plocate database with FSearch? I don't see much point in that, because the plocate database is missing some crucial data, which FSearch uses to make searching and sorting quicker. For example file attributes like size or modification date and the sort order by various attributes (name, path, size, ...) aren't indexed by plocate.

If plocate is faster at building the index, it probably makes more sense look at what's the reason behind that and add these improvements to FSearch.