Yes, this won't directly protect against an attacker whose goal is to create a botnet, mine some crypto on your dime, etc. However, it will protect against corruption of the O/S itself and, in tandem with other controls, can limit the abilities an attacker has, and ensure things like auditing are still enforced (which can be tied to monitoring, and also used for forensics).
Whether it's worth it or not depends on circumstances. In many cloud environments, nuking the VM instance and starting over is probably easier than fiddling with SELinux.
Whether it's worth it or not depends on circumstances. In many cloud environments, nuking the VM instance and starting over is probably easier than fiddling with SELinux.