>The Plug type myLink with Wifi was great, isn't it more complex using an external power supply plus LAN cable?

A connection via LAN cable has many advantages:

1) it provides the most reliable connection. On the contrary, wifi signal interference may result in loss of connection.

2) eliminates WIFI searching, connection setup, and password authentication. We have improved to provide a more reliable solution which is particularly important for Cloud-based solution. For your reference SmartThings & Philips Hue also use LAN cable connection.