Great dress!
I think it can be "casualized" a bit but as you say, it's inherently a dressy, or at least chic, polished, dress.
I think sandals and most open toes don't work as well. I think closed-toe flats would work, such as a good-quality more structured ballet flat or pointy flat; or a low wedge, or a slingback. It's not going to be a runaround dress, so I would not try to make it such. But it can for sure go from professional/dressy/date/blingy or more "approachable", like a LBD.