I also used Iamsmart last week. Was so easy. Hasn't been approved yet.
I did go to the transport Dept for my intl drivers license. Took 10 mins with an appt. However, the line was super long without appts.
I wonder which path is the fastest one?
Recently did mine online using the "iAM Smart" method. Takes about 5 days to get it in your mailbox from the day of submission. Just need to upload your VRD, Insurance coverage and recent address proof.
Not thru the app. You need to go to Transport Department's website to renew. You only use the app to sign the document. But before all that, you need to upgrade your iAM Smart app to iAM Smart+. Just need to visit a kiosk to upgrade. Kiosks are available all over HK MTRs and Post Offices. See links below.
Guide: https://www.iamsmart.gov.hk/en/reg.html
Locations: https://www.iamsmart.gov.hk/en/reg_location.html