Yes that is true. Even extended-range aerial precision-guided munitions don't have the same range as their missile counterparts.
But remember, long-range missiles cost a lot, whereas add-on kits to existing bombs a relatively speaking much, much cheaper.
And the PLAAF has a lot of older model bombs.
Using these kits on them gives them the option of a precision strike against important targets while allowing the aircraft to stand off from threats like MANPADS.
It remains a good way to achieve enhanced damage after degrading the enemy's AA defenses.
I'm sure the PLAAF will operate these - after all just look how many of their exercises still drop dumb bombs and launch ground attack rockets!
I imagine the most expensive part of PGMs and missiles alike are their guidance systems.
PLA may have a lot of older dumb bombs but the guidance systems are expensive. When you consider the converted PGMs will have far shorter and thus less useful range, I doubt PLA will purchase many in the forseeable future.
While it would be nice for PLA to replace their dumb bombs and FFARs with modern PGMs and ATGMs like brimstone, those weapons are not going to be useful for them in the wars they're looking to fight, on the budget that they have. They have limited funds, and are more oreinted to attacking airbases, radars, command/control centres, at stand off range rather than doing CAS or strike using non powered PGMs imo.
The fact that PLA are still practicing with FFARs and dumb bombs only means that it is the only cost effective compromise they can have to maintain some level of CAS proficiency among their pilots. In a real war, the chances of them using dumb bombs and FFARs will be next to nil. They'll be too busy launching stand off missiles at important enemy defense and communication nodes and fighting for air superiority to bother with CAS.
After all, you can't do CAS if you don't have air superiority, and for the PLAAF air superiority is hardly going to be guaranteed.
That is why I think shorter ranged non powered PGMs will not be useful to PLAAF in the near future and is why I think the majority of their strike weapons will be stand off range. Sure, convertible PGMs might be a little bit cheaper on a one to one basis, but if you need to get into an enemy's IADS or if you have to achieve air superiority to use it, then it is just a waste of resources.