Board Thread:General Mod Discussion/@comment-27272222-20160525211301/@comment-27324018-20160527180417

It's because they simply need to store more information than a simple block. The most info a block can store is an ID and a damage value (not really damage, but a bit of extra state info). If you want to store a list of names (like a banner) or a rotation angle (for a lot of the decorative entities you're referring to), you need somewhere to store that info.

Yes, chests and barrels and such can store a lot more information than a normal block and yet they are not normal entities. This is because they are ''tile entities. ''They are special entities that are specifically designed to be bound to a block. But though they could be wangled into doing things like banner protection, it's bad programming practice to derive from a base class that wasn't intended to serve the purpose you are turning it to.