LLQNH
You're right if you're only applying to jobs in HKG. However if you send to other countries they will need a Valid (less than 1 year old) HKG AR/IR to be able to transfer it to their license.
On top of that the HKG CAD temporary authorisation to renew AR/IR as it says is temporary, you can't take for granted that it will last for as long as you need it or that HKA will still be willing to renew KA ratings in the future.
It's little money to avoid big troubles, I advise everybody to stay current (less than 1 year) on their ratings.