A couple points. First "useful" is utterly subjective, and therefore meaningless. The usefulness of something tells you nothing about its origin i.e. there are lots of things that we find useful than can emerge from really stupid and simple cellular automata. Second, the entire universe is a computational engine. Nothing that exists is not a product of a deterministic process (in any local sense at least). "Programming" is meaningless because all dynamic systems in the real world are computational engines running algorithms. The behavior of DNA is as intelligent as the behavior of every other chemical process that is occuring. There are many other chemical systems that naturally exhibit the same behaviors; the fact that DNA is the one found in living organisms is actually pretty arbitrary. Some of these processes produce interesting results and others do not, but that is a feature of random processes and shouldn't be surprising.
That's not true. Volcanic eruptions are not "computational engines running algorithms." Nor is the Sun. You can simulate something as predictable as the orbit of the Moon around the Earth, but that doesn't mean that its every movement around this planet is dictated by a computational engine running an algorithm. Simulation should never be confused with reality.
In contrast to your misinformed claim, "programming" is useful because it differentiates intelligent intervention from random mutations or events.
"The behavior of DNA is as intelligent as the behavior of every other chemical process that is occuring."
Nonsense. DNA has an ordered structure that enables repeatable transmission of high-value data. Thus, DNA's predictable replication of various life forms is VASTLY more "intelligent" than the chemical breakdown of rocks that are naturally pounded with rain and rivers because the DNA predictably conveys information, whereas the stream does not.