Microsoft provides a suite of managed SaaS connectors that provide the following:
These connectors are essentially API Apps that are written and managed by Microsoft, then hosted in Azure. These connectors wrap the vendor’s own API, but provide a consistent user experience building on the developer’s existing knowledge. This takes away a lot of the complexity of working with vendor’s APIs directly. Note: you can still work with a vendor’s API directly by using HTTP connectors, or you can custom build a connector if necessary.
You can examine the JSON workflow definition after adding a connector to see how the connector is accessing the SaaS API endpoint. Using a MS Connector abstracts a lot of the SaaS implementation detail related to the specific trigger/action, and MS becomes responsible for dealing with changes made by the vendor as new versions of the service become available.