Definitely R&D, just imagine thousands of autonomous agents that are super-intelligent and are able to do science on their own!

Well, the most interesting one I can come up with is letting it work on improving itself, pushing towards the technological singularity.

Once it’s 10x as intelligent as a human, we can have it team up, build working nuclear fusion power plants, providing us with (practically) unlimited energy. Unite earth and bring world peace… I’d also advocate for deprecating money and capitalism and get us to Star Trek.