Samsung has promised that its next smartphones will have "64-bit processing functionality", which of course means nothing right now. As we mentioned before, 64-bit on a mobile device doesn't mean anything unless devices get past the 4GB of RAM plateau, or the software is optimized properly. Right now, the Android system is not optimized, nor are the apps. At least Apple has updated iOS 7 for 64-bit support, even if app developers likely haven't yet, but Samsung wants to add the feature to its marketing plan without bothering to wait for Google to get the system ready, meaning the term will mean even less than it does for the new iPhone.
As we said, it is possible that Google is going to introduce 64-bit support in Android 4.4 KitKat. It is most likely to be included if Google adds in the rumored optimizations to allow for Android to run on laptops. But, if those optimizations don't happen this time around, it is highly unlikely that Google will bother to add support. Samsung could add in some optimizations itself, but without system-level optimization, it likely won't mean much. Of course, like Apple, Samsung would be doing this for marketing rather than actual performance benefits right now.