I do get the range argument, but it really doesn't work that way. For three reasons.
1. A bomber can carry more similarly ranged ALCMs, thus applying more force to a target, or force to different targets by the same platform.
2. A bomber that launches an ALBM lits up in SBIRS and other satellites like a light candle. In contrast, ALCMs are stealthy weapons.
3. ALBM launch gives you the ability to design your first stage motor with a bigger expansion ratio (since the air is less dense at the point of launch), thus gaining a little more Isp and range from it. It is a common misconception though that you gain a lot of range from the application at hand.
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This is not a pointless weapon though, far from it. For starters, it gives greater reach to Chinas' nuclear triad, and also strengthens its second strike capabilities. It gives China the opportunity to field an air-launched ASBM, for supporting the PLAN on the Far Seas fronts. And it is an excellent R&D concept for additional applications, like ASAT delivery and even small launch vehicles (to supplement the rapid strategic replacement capabilities in LEO and SSO orbits that the CZ-11 and KZ-1A LVs employ).
Hope that helps, cheers..C: