The reason for this is they first need to prove to the FAA they can actually control these vehicles and land them when, where and how they said they would before they will be approved to try the maneuver over land.
The entire mission profile at this stage is just about proving out that it works and it will be safe to try put it down on land without risking hitting a building with a skyscraper sized stainless steel rocket.
Telemetry was as intended throughout the flight so it presumably landed where intended. They trigger an abort after splashdown, so the rocket explodes then sinks. And yes the remains, which is mostly just steel, then sinks into the ocean.
The reason for this is they first need to prove to the FAA they can actually control these vehicles and land them when, where and how they said they would before they will be approved to try the maneuver over land.
The entire mission profile at this stage is just about proving out that it works and it will be safe to try put it down on land without risking hitting a building with a skyscraper sized stainless steel rocket.