Upvoting can be seen or define from different angles. To me I see upvoting as an inspired tool to keep creating a unique content. upvoting shows that your post/writing has been seen, read and has help someone in one way or another. So the reader send a feedback through upvoting which comes with a token of appreciation.
And with upvoting you can tell how many people your post/writing reach hence makes upvoting important. So that the creator/writer can relate and work on the feedback (through the upvoting).

I invite @ owulama