Excellent explanation - thank you.
Agreed - just because you don't necessarily 'need' to adopt the practice now - you are setting yourself up for trouble later.
In the future, if/when Bitcoin becomes more popular and transaction blocks are crammed full of transactions, it becomes possible that transactions will take forever to confirm and allow a user to double spend (and thus you run the risk of being deprived of those funds, which could cripple a business).
Hmm, so it seems it gets 'worse' (the time it takes to confirm that is). Any idea how this could be handled at that point in the future ?