Mojo is a Python superset, Python is written in C therefore mojo is written in C.

I don't know what that rust library they benchmarked against is but given that they claim to have performed 50% better I would be sceptical. Given that most sources benchmark rust, C and C++ at about the same level.

I don't think you can trust because we can't verify the results they put out, plus iirc, people have done wild comparisons between mojo and different langs.

Not sure. I'd wait on more benchmarks with different libraries before making a conclusion