I just had a Navien tankless heater installed and the recirculating feature works wonderfully and needs no IoT app or internet connection at all.
It feels like we are in a wilderness period right now where every appliance wants its own app, with online account, which is just a supercharged way to get more personal data from their customers.
I also have a GE dryer with its own app. The functionality isn’t even good. We can see the settings remotely and get a notification when the cycle is complete.
In exchange for this essentially useless feature, GE gets a complete history of our laundry cycles, any info shared by my mobile device, and advertises to us.
Security is only a part of this mess.