I mean, labor aristocrats are still be proletariat. Socialism would be in the best class interest overall, but would cause a considerable decrease in the standard of living during the transitional state (I'd have to lose my treats during a revolution? ). Due to imperialism, the current unipolar order elevates entire nations to the level of labor aristocrats, meaning they have been sufficiently drained of revolutionary will. With this comes a destruction of solidarity with the rest of the proletariat. From my understanding, the idea behind multipolarity is that the ability to continue keeping the entire population of nations or international blocs in a state of labor aristocracy is vastly diminished or outright impossible in a multipolar world, as it gives nations who experience the worst of the exploitation bargaining power to uplift their nations and break away from the imperialists they are being subjected to. This would decrease the rate of profits, leading the group's bourgeoisie to relocalize the formerly exported exploitation, rapidly deteriorating the standards of living of those at home. This would drop the standards of living to the point that the offerings of the bourgeoisie are no longer sufficient for that nation's or nations' masses, leaving them better primed for revolution.

Edit: Sidenote: I don't actually think it's imperative for us Western Marxists to necessarily fully comprehend the idea behind it, as I don't see what action we take that would call for pushing for multipolarity that isn't already done under the banner of anti-imperialism.