I found it to be the exact opposite. ShareX has a lot of features which makes it hard to quickly get your head around all its clutter, when sometimes all you want to a screenshot utility.

Flameshot has key bindings just like any other screenshot program. If the shortcut is already bound by another program, then it will not let you bind it to Flameshot, I believe.

I have been using Flameshot portable for years and it isn't without missing features but I keep coming back to it. I generally use the copy function, sometimes save to location. It would be good to have a built in editor that can be loaded after the action.