The short answer is: Because that's how the site works.

Here is a list of privileges you can earn, and upvotes is earned at 15 reputation.

The idea here is that you are required to invest some effort into the site to get certain privileges - for instance by asking, answering or suggesting edits.

For general questions and answers about how the entire Stack Exchange model works, Meta Stack Exchange would be the place to visit.

The short answer is: Because that's how the site works.

Here is a list of privileges you can earn, and upvotes are earned at 15 reputation.

The idea here is that you are required to invest some effort into the site to get certain privileges - for instance by asking, answering or suggesting edits.

For general questions and answers about how the entire Stack Exchange model works, Meta Stack Exchange would be the place to visit.