Endless threads online are devoted to the topic, which often devolves into a drearily predictable form of bickering. On one side you have your crusty old coots (of all ages) who dourly insist that only an idiot would buy something so frivolous, and that you can either call yourself frugal or you can buy a _____ but not both. On the other side you have the dilettantes who trot out any number of self-deluded excuses, no matter how torturous, to justify their purchase.
How about this: let's try taking a "sensible snacking" approach to budgetary indulgences. Even the most self-deluded person wouldn't try to justify eating a carton of Ben & Jerry's after every meal, and even the crankiest of cranks can probably admit that a little ice cream once in a while is probably alright.