There are plenty of military uses for computing, but I also find it hard to believe anything but a handful of datacenters are or could be a major factor in anything but a completely 1 sided war. They are very vulnerable targets that are easy to locate and require large amounts of power and cooling. I also just don't see the application, encryption capabilities far exceed the compute available needed for decryption and computing precision and speed with even 20 year old tech far exceeds the precision of anything you would want to control. Even with tangible banefits, say 10% more or less casualties than there would be otherwise, in an exchange with anything resembling a peer military force im not sure it matters because everybody already loses.