Having the higher level abstraction built into the language gives extra semantic meaning that can be taken advantage of to build tooling. For example, one could

Having the higher level abstraction built into the language gives extra semantic meaning that can be taken advantage of to build tooling. For example, one could build a symbolic model checker based on the contract specifications. It would be possible to do the same with the lower level features, but a lot harder if they aren't used consistently and correctly. Same reason function calls are better than arbitrary jumps.