There's some benefit if you're Apple. 1. You don't have to rely upon whatever Intel/AMD decides is good enough for you. 2. You can design custom chips that

There's some benefit if you're Apple. 1. You don't have to rely upon whatever Intel/AMD decides is good enough for you. 2. You can design custom chips that fit your needs / possibly more secure chips to prevent hackintoshes if they wanted to swing that way. 3. It's competition to Intel/AMD if they wanted it to be. 4. It's another piece of the supply chain for your products that you control. You have to trust Intel/AMD's manufacturing chain.