What's the advantage of AWS Direct connect over VPN

Multiple VPN channels are required to communicate to multiple VPCs even within single region in AWS whereas a single AWS Direct connect can be connected to multiple VPCs within a single region.

Multiple VPN channels are required for multiple AWS accounts in a single region whereas a single AWS Direct connect can be connected to multiple AWS accounts within a single region.

You can get lower network latency in AWS Direct connect that in VPN. 

AWS direct connect is a dedicated line provisioning which handles the subnet traffic from your on prem site and then in to your VPC. VPN would be a good backup solution in case your ISP had an outage.