People that never use your supers: Why?

I am legitimately struggling to understand this. So many times in PUB groups for forges and nightfalls, people hold on to their roaming supers until the last 20% of the final boss. They don't use it to clear big waves of tough enemies, then don't use it to help kill minibosses, they don't use it when they're in a hard situation and need out.

For one, I'm confused as to why you're playing the space magic game, but not using any space magic. There's tons of shooters out there without space magic, why not just play one of those?

For two, you do know that you help give your teammates super energy by killing enemies with your super, right? Even Well generates 2 orbs, which provides a nice little chunk to help your friends out. Then they can use their supers and help you get your super back. Crazy, right?

Someone legitimately help me understand this "I'm never going to use my super until the last 15% of the final boss" strategy.

ITT: People that haven't cleared a raid or the forge once.