I bought a similar Ethernet USB hub and it’s been a real help. It allows me to add external as well as shared internal storage and provides an Ethernet connection. However, my Ethernet hub is a TP Link Gigabit hub but speed seems slower than what I get on my WiFi connection. Other than that it is a huge convenience.
The reviewers on the aliexpress listing of this item are mostly saying that the network port does not work on Mi Box S after upgrading to Android 9. Only the usb ports work. Perhaps Mi Box S users should avoid this and stick to the proven Ugreen one which actually works well for about double the price of this.
Just got this cheap usb hub/ethernet adapter and it works perfectly with the Mi Box S, the internet connection is full 100Mbit, the ports support my 2TB WD Passport HD (plays 4k Bluray Rips without stuttering in Kodi), and a wireless keyboard, with one slot free for another USB stick for quick transfers. This basically solved all my issues with the Mi Stick, just wanted to share in case anyone is interested.