WS Direct Connect uses private network connections into the AWS Cloud and is high-bandwidth and low-latency.

Build Hybrid Networks

private connectivity between AWS and your data-center/office (it uses AWS backbone)

increased speed/latency and bandwidth/throughput

cost effective if transferring large volumes of data from your data center to AWS.

Direct Connect does allows connection with a Region, not only to a VPC ( using virtual gateway - VGW) to private subnets, but to any other AWS resource (like S3 Buckets)

Cons are that it is costly and requires additional telecom and hosting provider relationships; also, traffic in transit is NOT encrypted by defaultand if you need encryption you will need an IPSec S2S VPN connection over a VIF (Virtual Interface).