When to use Jails with VNET, and when not?!

[Parsa Samet]

Would someone please give me a brief explanation of when to use jails with VNET and when not to? If VLAN-ing is not my concern, and services I use do not need a separate network stack - let’s say I run anything from DNS server to MailServer, Database, Java Application Server, VCS, CICD implementations, Streamers, Log Analyzers and etc., but believe they don’t in all scenarios need separate stacks - would there be anything else left for me to benefit from VNET?

All services I run on my servers are in a jail, and only some rare services are in an OpenBSD vm on top of bhyve. Also, I’m on FreeBSD 12.0-RELEASE-p2 with ZFS.