I personally never enjoyed her playstyle. You're constantly setting up turrets and watching them get destroyed---all while keeping a constant lookout for teamates to shield. It all comes off as busybody work for me. Too little reward for too much work.
She excels at maps like Ilios and Lijang Tower where she can "nest" on the point. She's also useful on hybrid maps, but once the payload starts moving, her usefulness evaporates. The exception to that is Eichenwald, where she's always useful due to the map's lack of alternate routes.