I think the suggestion was that, although Russia has faded as a major geopolitical competitor to the U.S. (though, to be sure, it still causes ore than its share of headaches for the U.S.) Cuba could eventually fall into China's orbit and become a useful geopolitical tool for them, just as it used to be for Russia. I'm not sure of what China would gain from that, though. I'm mostly just trying to interpret the comment.
This is my own person opinion, but I get the sense that China wants to expand its sphere of influence, but not in such a directly antagonist way to the US as Russia did.
While the US and Russia saw the entire world as a possible sphere of influence, I get the sense that China (at least for now) has a much more local focus.
I would argue that China doesn't need Russia anymore. That was why there was alignment in the past, neither country could face the US alone.
At this point in time I don't think China needs (or wants) to align with anyone else.