VLAN vs Private IPv4 vs IPv6 performance

I am interested in maximising linode-to-linode performance. I'm new to linode and networking so if these are stupid questions please forgive me.

The VLAN documentation reads "A VLAN is configured as a Layer 2 networking device on a Linode and provides low latency for latency-sensitive applications."

1) Does this mean the VLAN should outperform traffic sent over a private IPv4, or is it merely brochure talk to indicate operating a VLAN comes with no performance penalty?

2) I note that linode say traffic sent over IPv6 is "treated as private". Would that have the same performance as traffic over private IPv4?

3) I am also confused what this means on the VLAN brochure… "Streamline how your data is transmitted by segmenting traffic into smaller dedicated “lanes”, or multiple broadcast domains, to reduce broadcast traffic and application latency."