Analogies do not really need to be perfect to serve their function, the post quoted by the OP has as a message that if we spend money in all kind of luxuries and we do not think too much about it, then why do so with bitcoin and other potential investments which could in theory be way more beneficial than a luxury good? So even if the amounts are smaller and the luxury goods are different at the end the idea is the same, save some money and invest in bitcoin, maybe nothing comes up out of it, but if it does then that will be money very well spent.