You should upgrade to support the community. Tookapic costs money. A lot of money to maintain. We still need to spend our own money to keep the lights on. And we want to do it because we know tookapic is an important place for hundreds of users. Every penny counts.
Secondly, becoming a Hero(especially if you purchase annual subscription) will motivate you to completing your 365 project. Users who bought Hero subscriptions have much bigger chance to complete the challenge.
And finally, you should upgrade to unlock features that are unavailable for regular users. That includes using your own domain name, professional templates and access to your profile stats.
It's simply worth it.