The advantage of a keyboard-initiated search is that it works in all apps (or damned well should).
Mind: on Android, with a keyboard (bluetooth), poor app support is frustratingly apparent. Even where basic keyboard input is recognised, obvious things don't work as expected.
In Pocket, the backspace/delete keys won't delete tags.
In PocketBook (an eBook reader), hitting space when entering a search term (which cannot be initiated with Ctrl-F) ... scrolls forward in the document.
Etcetera, etcetera, etcetera...
