Sa AT kasi engine braking depends on your torque converters stall speed. once your revs go below stall speed, more or less parang free wheel ka na. thats why push starting an AT needs lots of speed.

Mas maganda engine brake cuz it acts like an ABS. pero tama din na engine braking wears out the clutch faster and brake pads are cheaper and easier to replace. Explanation nga sa book, todays brake systems are very resistant to brake fade and overheating so it is perectly fine to not use engine braking. Practice of engine braking began with the older cars which had no vacuum assist. Braking was a back breaking job so people opted to used engine braking to slow down.