I thought there were no Russian uses for Pakistan as stated earlier by you, now suddenly you have started to find things, even if "marginally".
Moscow can gain greater access to Middle Eastern and African markets through CPEC, crucial in these testing times of EU sanctions, a fact not lost on Russian policy makers who were quick to support the project hoping that it can be extended to ex-USSR states. Also, engagement with Islamabad, makes certain that American influence in the region is kept in check, as well as being an effective answer to the growing New Delhi-Washington ties. And making certain that extremism and violence doesn't spill over in the Central Asian states, Pakistan can help greatly with that, not just "slightly", being a major player in Afghanistan for decades. Know something better than the Russians do, again? All of this, was already there in the excerpts I posted above, try to read them next time.
And you still haven't answered my basic question: Why go to all this trouble, if there's nothing in it for Kremlin? Why is there something, instead of nothing?