The PRC doesn't really need additional strike assets (IMO). It seems to me the primary role of PLANs CVWs will be CAP, in which case long range would be nice but not altogether useful: if you're stuck to helo AWACS platform that can only see out to ~150km, then you're CAP isn't going to be able to venture too far from formation its covering anyway. I don't think J-20 brings much to the table as an interceptor without a fixed wing AWAC platform in support.
If they're operating in the South China Sea then couldn't they have land based AWACS support?
Then why not used land based fighters? All that would be necessary was a sufficiently large tanker force or forward island basing, one of which they have and the other is far easier to establish than a carrier capability. Inside the first island chain a CV brings nothing to the table that the Chinese couldn't do with land based air. Its just a pricy target. Their long term goal I believe is to have a CSG capable of operating out of area, something their land based assets can't effectively do without minimally crossing another country's airspace or ADIZ.