They're long term temp fixes. If you use Sharkbite correctly it should last a minimum of 25 years. I think they're great for first time DIYers. Lets you learn basic plumbing and build up some confidence then you can transition to something else once you understand their limits.

Although quite honestly if you really want you could use Sharkbite forever. Just check them over every decade and replace them if you see a problem. You could literally replace one every 5 years for the rest of your life and it would still be cheaper than calling a plumber out once.