extraordinary, fabulous
瓌 centers on something exceptionally rare and wonderful: extraordinary, fabulous, like a gem that stands out from the ordinary.
瓌 combines 王 (jade/jewel) with 褱, which likely contributes the sound and the idea of something precious or held close. The exact historical development is uncertain.
The left side 王 (jewel) marks something precious, and the right side 褱 looks like a treasure wrapped in cloth. Together they suggest a fabulous, extraordinary gem.
For カイ, imagine a fabulous kite (カイト) made of extraordinary jewels: kite -> カイ, and the jewel-kite is truly extraordinary.