Do you mind explaining what that means? if somebody tells me that I'm going to get 64 bit support I might say I don't need my bits in a support... But such a bad joke would demean the quality of the discussion. More seriously, I understand 8, 16, 32 and 64 bit OS. More bits means more instructions per CPU cycle, means more work accomplished in a given amount of time. But what does this mean to me as a photographer in post-production?
64 bit means that LR will be able to use more than 4GB of memory. This should give you better perfomance when you're dealing with large images.