Apparently, these ARM chips are quite good at their jobs and Microsoft might try converting entire categories of workloads over.
Legacy x86 Windows applications have been a millstone around the neck of the entire industry for ages now and its long past time they were relegated to a niche and left to quietly slip away into the night.
What's interesting here isn't that Microsoft managed to take its existing code base, strip out some of the cruft and compile it on ARM.
What's interesting is what Microsoft's experiment unlocks outside the Windows ecosystem.
This means that - for server-based ARM chips at least - hardware can be talked to using a generic ARM ACPI driver.
This is what can and will allow every flavour of Linux, BSD and whatever else to run on ARM CPUs with minimal fuss or headache.