@temitopebanks first your on the right blog to learn those things.
First have a look at the rest of @taskmaster4450 posts, along with @hitmeasap and @fulltimegeek they all have some great articles to help you understand steemit.
If I had to answer I would say vote value is win win for both people.
Let me put it this way if I had the power to reward your question with say $1 does that make you more or less likley to want to engage with me again?
I'm going to guess more likley right which increases my chances of you seeing my content and hopefully something you like and up vote.
See win win its incentivised comunity and content