It is a VERY important change. They don't only get 100% of their upvote, they also get more from the curation of others' upvotes on their posts, including those coming from promotion services like bid bots.

100% of the curation rewards from their vote, and a portion of the curation rewards coming from everyone who votes for the post after them. This gives the author an unfair advantage over other curators, because the author can earn additional curation rewards through self-voting.