For the nearly $4k USD price of a PE ticket to the US, you can probably find a ticket in J on a oneworld carrier for a similar price.

Example:
HKG-LAX-BOS on AA in J is $3,800 USD. Earns 200 CP.
HKG-BOS on CX in PE is $4,500 USD. Earns 100 CP.

No brainer, here. Unless you're seeing drastically different prices, that is.