Yes, good question! Steem Power influences earnings from curation. It also influences your vote worth and the ability to help or to earn through delegation.
I didn't go into all the details here, but I've written before in several posts, the main objective for new members is to power up everything they can to Steem Power, so that they can increase all of the above.
If the information can be found in different places it's a good thing, because you can see more opinions or different ways they are presented. Yes, sometimes simpler explanations are needed!