Oneworld members need to grant each other access to their ETKT database and allow them to exchange/reissue the coupon - that is a major technical difficulty considering the different GDS they use, along with the settlement price for first and business class award seats which is hard to agree on. ...

USB-C charging port is a really nice touch though.

Jetstar isn't a oneworld or oneworld subsidiary member. So sadly no. Unless: you are gold or above with Cathay traveling on CX codeshare, then you got access to CX-operated lounges.

Short haul domestic flights also serve as feeder service connecting to or from international flights. If airlines and train companies could interline and the transfer experience could be better improved, I would be happy to consider trains as an alternative option.

People seem to forget taxation.