This could be usefull for High-Availability / Fault-Tolerant applications. I think 10 years ago, Ericsson had a highly available server machine for Telecom app

This could be usefull for High-Availability / Fault-Tolerant applications. I think 10 years ago, Ericsson had a highly available server machine for Telecom application, named Jambala. It had 2 SPARC and 2 x86 CPUs. Having two different ISAs in the same system can protect you from subtle software/hardware errors. So you compile you code to both targets, if for some reason one of x86 CPUs fail, the second x86 takeover, if both x86 fail, then SPARC CPU takeover, etc. Off-course this system run Erlang/OTP ;)