I think that it is always good to need something and never having to use it, as opposed really needing something and not having such a thing to put to use. Nuclear weapons are no different in this regard. Better to have them and not need them, then the alternative.
We do not need nuclear weapons in today's world. If aliens come to fight the people of the world, they will be so advanced that a nuclear weapon will not save the planet. We currently have enough ways to mine for minerals and ores that nuclear weapons are not needed for that purpose.
If movie aliens came we'd be so screwed. I don't think a nuke would do much. I would use it to kill myself so I wasn't... experimented on. And there is a good chance that we wouldn't even be able to get to the nukes to fire them. The aliens might destroy them before they enter our atmosphere to protect themselves.
Suggesting nuclear weapons should be used for mining I'm dearly hoping is a deliberate outrage provoker and not a serious statement because that's a terrifyingly misguided concept. As for meteors, we can blow something up without nuking it, I don't think that's a valid reason for them either. The only way nukes are going to get used at this point is if a terrorist gets their hands on one and a means to detonate it, they otherwise sit there to promote mutually assured destruction and nothing else.