Unless you route and routine is identical and symmetrical from one day to the next, the estimated range indicator is not going to represent reality. Let's take a fairly common situation...say you live on a hill or maybe near the exit of a major highway. When you've coming home, the last miles driven are done at high speed and maybe uphill. The estimate for the next day will be MUCH lower than reality for most people, depending on how far you actually drive because it is based on the last 18-miles of your driving, which may not represent reality, or the fact that in the morning, going downhill means your distance traveled per Kw is much higher than coming home.
So, anyone who focuses on the estimated range indication of reality, unless they've verified it in real life, is missing a lot of flexibility on the use of the car. It is not uncommon for me to drive maybe as many as 10-miles with the estimated range never going down based on different conditions, either traffic, route, load, or weather. Just like the estimated range to empty on an ICE is just a guess based on last driving, the GOM on the i3 is as well. Changing where and how you drive can make it change. Rely more on using the average miles/kw, and the nominal size of the battery pack, and you can get a better estimate which may be more current than the last 18-miles you drove.
This tends to be the major issue with any EV...added to the fact that there often aren't easy and fast charging opportunities, and you can never refill as fast as an ICE.