Having somewhere to look them up is good, but the problem is that you can't be bothered to do that all the time. For instance, I'd have been stung by the fake Share tripcodes if I hadn't been tipped off by some other search results for the same search. Having the tripcode in a form you can instantly memorize would be handier. And memorizing 60 bits of data can definitely be easier - the current format of the data is particularly hostile to memorization.