I have never decorated a cake in my life, nor made fancy pastries - so why do I consider this an essential kitchen tool - and how did I wear out the old one that came with those metal nozzles?
this is very easy to answer. Cuisines of the world are full of wonderful stuffed things, stuffed eggs for a simple example, that are just too much trouble to make - unless you have a piping bag. Then they become ridiculously easy. Just put your stuffing in the bag and squirt it into or onto whatever you are making.
When you buy a set, make sure it has a 1/2 inch plain nozzle. That's actually the only nozzle I've ever used - because I don't decorate cakes. If your's doesn't have that nozzle, they are available on the Internet, for instance the Ateco 806 1/2" Plain #6 Pastry Tube (2015 US $1.09). The version shown in the photo uses cheap disposable bags, but I wash the bags and reuse them anyway - because I'm even cheaper than they counted on.
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