Makes code more clean because it is shorter and the use
keyword is not needed anymore.
It feels like an anti-pattern, we still have traits to fix this kind of thing. Multi-inheritance is not possible unfortunately, but an interface should not be misused for this.
I understand the downside of not having multi-inheritance available in PHP. However, IMHO this should not be solved by allowing implementation specific code in interfaces. That's not what interfaces are meant for.
It looks pretty much the exact function as abstract class. I still think interfaces/contracts should not include any concrete implementation