Since Wiktionary is case-sensitive on first character ($wgCapitalLinks is set to false), searching lower-case titles on mobile could be frustrating if auto capitalization is enabled. The fix is just adding autocapitalize="off" to the search <input> element.
Maybe this can be automatically done in any wiki that disabled $wgCapitalLinks?
Using $wgCapitalLinks sounds fine. It may require copying across the autocapitalize property in the client.