We don't necessarily care about matching absolute production performance, but could throttle things to get the right ratio between performance of CPU, memory bandwidth, disk IO, etc, in order to explore which code tweaks will have the biggest relative impact on your workload. It would let you do a bunch of your testing and optimization locally, for free.

Could be an edge to distinguish you from the competition, although I'm not sure it's a big enough one to warrant a business case. Maybe it would be attractive to shops whose development costs are high compared to production (i.e. startups and enterprises with lots of ongoing customization), but probably not so much for the established, internet-based businesses where I'm guessing the big money is (like Netflix).