This curve is a change from pure linearity and is designed to mitigate exploits at the lower end of the curve – where users can upvote themselves small amounts of rewards, mostly undetected, without corroborating votes from other users. The purpose would be to help prevent “leaks” in the system where spammers and other “abusers” or exploiters can reward themselves for low-value content due to today’s linearity in the allocation of the daily rewards pool.

How much abusing in the system? Need more detail info about it. Which part of pool was robbed by its?

This distribution change for content creators and curators moves the current 75/25 split in favor of authors to an even 50/50 split. It is designed to entice more staking of STEEM tokens and more participation in the system for content discovery and ranking.

Unfortunately. Why I need live curation if I can earn more steem just delegating my vote to bidbot? What better million or billion? If I can get billion instead million I take billion.

You can check this post. I guess we can get more productive proposal