Can you not use mining lasers on them? I haven’t been to one in a while, when you say no resources what exactly do you mean?
I've mined them, they're asteroids just like all the others, perfectly minable and plenty of resources, of course this was pre-blowy up days so I don't know if they have added explodable asteroids to them, I will have to check one day.
Reality may work like that, but this is a game, if it is there someone implemented it. It once had a purpose, the game changed and the DEV's forgot about it.
This is a game trying to create an as true to life model of the galaxy as possible, the stellar forge is designed to evolve solar systems from primordial spinning clouds of dust, this results in planets, stars and leftover material that doesn't make it into landable bodies, procedural generation don't you know! They are already there in the solar systems, the stellar forge modeled them, we have asteroid models already in game, why not put them in? And no they have never had a use. The same argument can be used for a lot of other things. A lot of players have asked for comets for a long time, even if there is no current game play associated with them, no doubt if they were in game you would also be wanting them removed because they are "useless".
I am quite happy to have things in game that are of no other use than to extend the model of the galaxy. Asteroid clusters are part of asteroid belts, without them there is no way of actually interacting with an asteroid belt, sometimes the clusters affect your entry to the system, they affect the local gravitational gradient and slow you down, they contribute to the total mass of star systems as created by the stellar forge. It certainly isn't perfect, but they already exist due to the way the galaxy is modeled, so why not have them in?