The payment of small sums of money at regulars, comfortable intervals over a period of time, rather than paying the whole amount at once, has obvious advantages.
If you have to buy anything, or pay for something which supposes a big and unexpected economic cost, but it’s absolutely necessary to do, say a new washing machine, repairing your car, and the like, then paying by instalments can be the best option. But you have to watch out, because you must to keep in mind that you will have a debt to pay at the end of the day.
On the other hand if you know what easy can be to pay right now for something you have a craving for, say a new smartphone, a journey, a pair of trousers, whatever, that’s an entirely different question. In this case, it should be better to thing about it twice before spending some money don’t have, in fact.