It's all about how willing you are to compromise your 'normal' car trip experiences. About the smallest gas tank on any ICE will still get you at least 200-miles without much difference summer/winter, and could be significantly more (mine will go 500). And, there's over 100K gas stations in the USA, each with multiple pumps that can refill the car in less than 10-minutes with rarely a wait to get to one. In most cases, you don't really have to think about where you want to stop much. That is NOT the situation today when driving a car like the i3. Even if you can find an EVSE or CCS unit, there's no guarantee that it is working or that someone isn't using it (or parked to block your access!). Then, that refill rate can vary significantly from maybe a low of 10A to 32A for an EVSE, and anywhere from 10Kw to 50Kw on a CCS unit. Note, on the EVSE, even at its maximum current rating, many of them do not use 240vac...208vac is a more common commercial supply, so that decreases the charging performance by about 20% (power = volts * amps, lower the voltage available, and even at the maximum current, your result will decrease).
Yes, you can find a quality gas can to fit in the i3's frunk...that may have no saving grace should you have a frontal accident...that area IS designed to crush. Now, your odds are low, but do you run with scissors or knives? Best to be safe verses sorry. Only you can asses your risk tolerance levels, but it does help to be informed of the potential consequences.
There may come a day when long-distance travel with an EV is as simple as today's case with an ICE (fast, numerous charging options). But, even with Tesla's supercharger network, should you wish to go the path less traveled, you could be far away from one, and need a long time to get your vehicle back in operation. The REx was designed as an emergency backup crutch...it works. It's not the best way to travel long distances. Other hybrids are designed for this...the i3 was optimized for maximum efficiency, not maximum range so compromises had to be made. Today, you can't get one configuration for everyone. Maybe never will.
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)