Automatic transmission saves you the hassle of working a clutch.
Tips
usage
In mainland car talk the more common terms are 自动挡 (zìdòngdǎng, 'auto') vs 手动挡 (shǒudòngdǎng, 'manual / stick shift'). 自动挂挡 emphasizes the action of shifting; you'll see it more in technical descriptions and Taiwan/HK auto press.