Google has many different products and some like Gmail, Google Chat, Google Voice, and Google+ can be used to add and remove contacts. A common interface for managing all of that makes sense.
Google says that the feature is being rolled out gradually, but you can try out it out at google.com/contacts. The Google Support page also lists the simple steps to access the Call and SMS buttons for the person you want to get through to. For a particular contact, simply hover over the phone number field on their contact card and then select either the phone icon or the SMS icon.