Like I said, they're not cheap. Some years ago I paid around €80 for the type shown in the photo, and checking just now, I see it costs closer to a hundred now. So definitely not something most modellers really need, but for the kind of modelling I do, it's a good investment because it will save a lot of work and aggravation trying to make little discs in other ways. If you only need the occasional one, your punch will be quite sufficient, or for example cutting discs from plastic rod.