Depends on your use case. If you want to run VMs directly from your NAS, it's useful. ESXi is in no comparable to it. I see using a VM as a basis for DSM as a good thing. For Synology it could simplify their code base across all their machines. For us aside from the security, it opens up the amount of software we can run, and as I'm sure you've all noticed, the Synologies need all the help they can get in that department.