Nope, but they care that their pictures look better, their games are snappy, etc.

Since it only has 2 gigs of Ram, 64-bit won't do anything for any of that.

64-bit address space might not; 64-bit integer registers might help speed up some non-GPUizable matrix math.

It won't make an iota of difference, since the phone has less than 4 gigs of memory.

Wait, you asked if they 'cared'? Of course they care - it's a larger number than everyone else at the offices' iphone has.