FKDR is used in hypixel to bedwars to measure "skill" (even though they ignore actually important stats like:
Wins/Loss KDR
BBLR
But of course final kills and star level is where the skill is honed.
Bottom line, if you have a high FKDR, you will get invited to many bedwars games because people think this means skill. In reality it means you probably just steal kills or main solos. If someone doesn't let you in their game because of this, don't worry because it is highly unlikely that it would be a fun game.