Google Editions just launched: Differing network/radio details. What does it mean?

I note a small difference in the "Network" sections of the new Google Edition sets on the Play Store.

HTC One at https://play.google.com/store/devices/details?id=htc_one says:

Network
Unlocked GSM/UMTS/HSPA+/LTE
GSM/EDGE/GPRS (850, 900, 1800, 1900 MHz)
3G (850, 1900, 2100 MHz)
HSDPA 21, HSUPA 5.76
4G LTE (700 MHz, AWS)

Galaxy S 4 at https://play.google.com/store/devices/details?id=samsung_galaxy_s4 says:

Network
Unlocked GSM/UMTS/HSPA+/LTE
GSM/EDGE/GPRS (850, 900, 1800, 1900 MHz)
3G (850, 1900, 2100 MHz)
4G LTE (700, 850, AWS, 1900 MHz)

While each page notes that both sets will work with ATT or T-Mo in the US, the extra bands on the GS4 must be there for something. Anyone care to explain or speculate?