It’s not a terrible idea to get a wifi dongle if you have the budget for it. 99% of the time you’re fine. In all the workspaces you can assume that wifi will be present so that’s not the issue. But I had to configure the router in my apartment one time and doing so required that I was physically plugged into it. I suppose I could have just opened a support ticket and had someone else take care of it but I had the ethernet cable and dongle so I was able to take care of it on my own.
So in summary: not necessary to have ethernet but it’s nice to have that option if you ever need it.