I'm not sure on what Enhance 2.0 is, haven't been in HKG, but it does seem likely a fairly poor implementation. On the way back I got an Op-Up(after declining a 2000HKD each way offer to BKK), which means Cathay left around 1000HKD on the table (about what I'd of probably paid). Hopefully they are running some testing to work out the right structure and wise up. In my case my employer forces me into economy on shorter flights, but on occasion I'd be willing to spend my own cash for a better journey.

Hopefully the upgrade bid moves more towards BA's paid upgrades, i.e. more of a token amount rather than the cost of upgrading your ticket, and also giving you the tier point credit of business class, rather than the underlying fare.