Not sure what they are referring to by higher sound quality. I don't think its the latency as that wouldnt matter so much with music and podcasts. Maybe if its BT5 it can stream higher bitrate.
From Apple Website "Powered by the all-new Apple H1 headphone chip, AirPods deliver a faster and more stable wireless connection to your devices — up to 2x faster when switching between active devices,3 and a 1.5x faster connection time for phone calls.4 The H1 chip also drives voice-enabled Siri access and delivers up to 30 percent lower gaming latency.5 So whether you’re playing games, listening to music, or enjoying podcasts, you’ll experience higher-quality sound."