Solutions like Azure Express Route and AWS Direct Connect are great as they give you a dedicated network connection from your on-premises Data Centre or Co-Lo directly into the Public Cloud. These can scale up to 100Gps of performance!
This suits use cases where your applications are latency sensitive and you need to transfer a lot of data over the network for things like; backup and disaster recovery replication and for communication between applications that can be spanned across on-premises and the cloud or applications that need to talk to others that are in different locations.
These connections make the cloud appear like an extension of your on-premises data centre.