The entire concept of a "symbol" is a very human thing -- there are no natural symbols outside the human mind (except maybe inside of a computer, a human invention). Do you need to use symbols in order to organize matter into "technology"?
Edit: it occurs to me that DNA/RNA are made of natural symbols, which is a pretty good argument for symbols being important.
I think all of this is explained by a linguistics 101 course (I have seen a few excerpts of one lecture).
A good reason to use symbols in communication is for reliability (which is needed in the DNA). With a discrete set of symbols you have most likely no degradation (instead some recovery occurs -- like when you interpret a poorly written letter), and with a small chance you understand a completely different symbol. This stops error propagation.
Moreover, symbols allow for easy combination, which expands indefinitely the vocabulary with a fixed cost.
Edit: it occurs to me that DNA/RNA are made of natural symbols, which is a pretty good argument for symbols being important.