Metal was announced back at WWDC, and Rebellion Co-founder and CTO Chris Kingsley has stated that he saw its potential as soon as it was announced:
"We’re excited to be working so closely with Apple’s technology in our Asura Engine as it will empower us to code to Metal, remove some of the main rendering bottlenecks, and bring even better looking, more immersive games to iOS devices. Metal is leading the way in the next generation of mobile rendering technologies. It could be a real turning point for mobile gaming."
Whilst no games were mentioned, it's very likely that we can look forward to some Rebellion games coming out and using the new 3D API sometime in the future.