That photo is a case study in how cute people are generally bad judges of these things in general. There's a bunch of things going on with that outfit that could become a complete trainwreck if you were heavier/shaped differently. Luckily, you are Manda, but I still don't really think it's a great outfit in general despite the fact that you are adorable.
Anyway though, I don't really care too much about sandals. I don't like them and would never wear them, but as Drill King said, they are casual wear and I don't get all huffy when I seem them. They're not horrible, I just doubt I'll ever see someone wearing shorts and sandals and think they look sharp.