It is actually an indication that the car is mostly operated in hybrid mode. That is a good thing for the main traction battery which indicates that it didn't get much cycling. However, it means the engine got a much more work load during this time.
Battery will age even if it isn't used much. So, there is still wear and tear on the battery even if it is less used.
Either way, the powertrain should easily last to 150K miles without any issues. The big question is that did the original owner properly maintain the engine by changing oil at least once every year.