There were also enterprise and military customers using it for damage reduction. Some used products from Tresys that made configuration easier. Unfortunately, the tremendous number of 0-days and leaks in Linux platform made high-assurance community push for putting apps in VM's on separation kernels. The rise in hardware attacks meant even those aren't enough: physical separation with EMSEC sheilding is required.

Most aren't going to do that, though. So, their boxes are still nice targets.