One of my fav companies! Dor is an amazing person, highly recommend working with them. We started to move to ScyllaDB at my last engineering job. Doing 100TB’s a day in IoT Data.
My last job was far less data than yours (more like 100's of GB/day), and it wasn't surprising it handled it with ease. I love that DB so much. So performant, and far easier to admin than Cassandra.
For IIoT, there's digital twins, machine health, sensor data aggregation, and a lot more. While a lot of it can be classified as "write once, read hardly ever," it is vital for triggers, alarms, real-time failure and security alerts, and, eventually being forwarded over to analytics systems for longer-term trends.