A CDN *cache* server is a special case. Netflix cache appliances can accept the risk of running FreeBSD -CURRENT and upgrading half their fleet to the latest snapshot every ~2 weeks and we thank them for battle testing FreeBSD's active development branch in production. It really helps to reveal regressions (both correctness and performance) early in the subsystems and drivers that matter to their usecase.
Most users will neither be willing nor able to accept the trade-offs that Netflix chose.