Pro: As you've probably heard, you could find a magnificent Anglo-Saxon treasure trove!
Con: More likely, you are probably just wasting your time on the "world's worst hobby."
This is like playing the lottery (or, what used to be called the numbers before the state took it over). Probabilistically, it is a waste of time and money (why I don't play). But your chances of winning are finite (albeit slimmer than I have been for many years).