In an ideal world yes. Or if your software works already seamlessly cross-datacenter. But in the real world is rare that your hosting provider is good at both VMs and metal. At least that's the biggest problem I've always encountered, specially with budget providers.

This is clearly the ideal setup for most use cases, and I'm somewhat puzzled as to why it's not more common. I guess using only virtual servers is a tiny bit simpler, so companies will just eat the extra cost.