Just to share my experience on autogate at Suvarnabhumi Airport.
When you arrive at airport, the manual clearance lane is on the left and autogate is on the right. Only the first 2 gates are reserved for Singaporeans. Scan you passport as per normal and you need to scan you boarding pass at the scanner located in the middle of the autogate (pls look at photo on 1st page). There are 2 Customs officers to help travelers so not to worry too much.
Once you clear the 1st gate, proceed to 2nd section to take a photo and scan your fingerprint, not using thumb but index finger.
Once you clear the 2nd gate, you will see a small desk next to autogate. A Custom officer will stamp your passport and tear the first portion of your card.
This is semi-auto clearance and not fully automated clearance. It clears pretty fast so I'm not complaining
No change in departure, still need to go thru the pain.