A cyclo-cross bike that had been quite successful in world cup and UCI championship races has a similar feature, IE a top tube bent up. Cyclo-cross is very stressful for the materiel. In this specific carbon frame this bend is apparently not a significant weakness.
The same manufacturer also offers an aluminium version of the bike. Of course that's isn't race tested to such a degree.
The main reason for this bend is to bring the top tube up, about level to the ground, while exposing as much of the seat post as possible. For a cyclo-cross bike a high top tube is necessary as it makes shouldering easier.
The bend also allows the seat stays to attach at a shallower angle to the seat tube while joining at a nexus with the top tube. This in turn is supposed to improve rear end compliance.
The manufacturer also claims the bend would be beneficial to general handling, stiffness, and compliance characteristics in the typical vague way all manufacturers talk about their stuff.