Add me as another user that would have preferred a model with Ethernet (I almost didn’t buy mine because of it being WiFi only). I would also buy a second model with Ethernet to replace my current one if given the choice.
In my opinion, WiFi gains adoption with things like Arduino and RPi because they’re marketed to people who want to tinker and learn so it’s all about convenience. Hobbyists can play with a single-board computer on their bench or in their living room on the TV, they can take their toy to a friend’s place for help, they can create battery powered sensors/loggers that are portable, and students/teachers can put them on WiFi in a classroom setting to avoid a tangle of wires. WiFi also helps to sell cheap “smart home” stuff so that the barrier for entry stays low - a potential buyer doesn’t need to hire an installer and run wires just to dip their toes in home automation. The manufacturers know that ease of use and vendor lock in are what matters most to their bottom line.
WiFi capable IoTaWatt models would still always offer a big selling point for people that can’t or don’t want to run a cable to their panel, but I would imagine many of the people purchasing the IoTaWatt are a bit more savvy than the target market for a color-changing “smart” bulb, who would welcome an Ethernet jack in many installations. I know there are many out there who wish the IoT market in general offered more products with the option to use a wired connection. I for one would love to see more IoT devices that support Ethernet with PoE when possible for one-wire installation (see wESP32, no affiliation). Obviously with regards to the IoTaWatt, it needs its AC reference input and will already have many wires run to the electrical panel so PoE would be of limited benefit for this particular application (though it would still mean one less bulky transformer to plug in for power).
Wireless networking is great at home for mobile devices that come and go or move room to room like your phone, tablet, and laptop. For anything related to infrastructure that stays in place and is always running (IP cameras, alarm systems, access control, etc.), wired is almost always the preferred option for quality products. IoTaWatt is a finished product (in contrast to hobbyist boards - I’m not talking about ongoing development and product improvements) meant to be installed and left to do its thing as opposed to being a device intended for a technician to carry in their bag (even though it’s a great tool to have in one’s bag!). While I understand all of the issues you raise overeasy, and agree that they’re worth taking into consideration, I humbly suggest that there should be an option for an IoTaWatt with a wired connection in the future.