A soldering gun is this device here. This is a handheld version. It's 230 watt. So it's a very, very high powered device and this is made for soldering rather heavy pieces. Pieces that you're not likely to find on a printed circuit board.
You may find heavy connectors or pieces of brass or other things that have a lot of mass to them. These may require higher heat than your able to get from a smaller soldering iron, which may only put out tens or a 100 watts.
So this kind of device you're not likely to encounter this in a typical electronic soldering project. But you may find this useful for heavy connectors and other things that may require more heat then your typical printed circuit board. And it reaches temperatures much, much higher than you get with a soldering iron.
And it's useful for soldering very heavy parts that we're not likely to encounter on a printed circuit board but perhaps electronic connector or something with high power. And it reaches very, very high temperatures and even turns glowing cherry red.
So not only is it high temperature, but it's something that you'd be very careful with. Allow it to cool before you set it down or forget it. And you're not likely to use this for any kind of circuit board with components like this for electronics. This will be more for high power electrical work. Stuff that you're not likely to encounter on a printed circuit.