The Skydweller is capable of carrying an ISR (Intelligence/Surveillance/Reconnaissance) equipment load, which is several times heavier than the Zephyr -- not to take away from the Zephyr's accomplishments ("on the shoulders of giants", etc).

The article mentions "wide-area surveillance"[1], which translates to "a lot of cameras" (FLIR, visible light, etc).

You also need more solar and more batteries to power all that ISR.

1. https://en.wikipedia.org/wiki/Wide-area_motion_imagery (eg. GORGON STARE)