If one uses HKIA as a transit point or one uses the kiosk check-in all the time at HKIA, then I think it is possible that one is not be given a buggy voucher.
Whether one wants to take the buggy service or wants to walk after hours of sitting onboard is really a personal opinion that I can keep to myself. (
Edited to say I should have kept this opinion to myself, perhaps. 
)