Question

why is DNA good for storing huge amounts of genetics information?

Answer 1

...you could say that it's ability to condense into highly organized structures is the key property which enables it to fit within the nuclear envelope. But that answer is technically incorrect because this "packing" is done by histones and other scaffold proteins.

Answer 2

I would say, it is because of the complex methods of gene expression. A good thing to look at would be Human Immune System. If we had to directly code for every individual protein used in Human-IS, the entirety of our DNA would be devoted entirely to that. However, because of gene expression mechanisms--we dont have to do this. It's rather elegant, really.