In a centralized management scenario, the central controlling service needs the ability to control everything registered with it. So, if the central controlling service is compromised, it is very likely that everything it controlled is also compromised. There are ways to mitigate this at the application level, like role-based and group-based access controls. But, if the service itself is compromised rather than an individual's credentials, then the application protections can likely all be bypassed. You can mitigate this a bit by giving each tenant their own deployment of the controlling service, with network isolation between tenants. But, even that is still not fool-proof.
Fundamentally, security is not solved by one golden thing. You need layers of protection. If one layer is compromised, others are hopefully still safe.
Realistically, probably not. If your workload is highly memory bound, and sensitive to latency, you would be leaving a little performance on the table. But, I wouldn't stress over it. It's certainly not going to bottleneck your CPU.