Again, I appreciate the thought. It's a brand new technology and this is apparently how it works right now. It will likely greatly improve in the future just as Apple laptop battery power has greatly improved over time. If brand new tech must beat existing tech in every possible way, there is likely to be no more brand new tech. Sometimes it takes a step back in a key thing or two to take several steps forward.
Look at electric cars. Not many years ago, they had extremely limited range on a single charge. Had everyone judged & juried them on that then, there would be no improved electrics now. The majority then were clearly against spending MORE-TO-MUCH-MORE for a new car and always having to worry if they had enough charge to get to and from destinations. However, progress continues to be made and now comparably-priced electrics can do very well against gasoline-based equivalents. The range worry is fading fast.
I certainly wish that this device has 100 hours of battery life or maintained full charge by solar cells but it doesn't. That's a definite weakness in the overall proposition. On the other hand, here's a portable device that has no crease in the screen, no fragile roll, does not scale up in weight as you scale up the view screen(s) SIZE you want to watch, etc. Unfortunately, rumors say one battery pack yields only about 2 hours of life and 2 packs yield 4. I'll probably carry 2 or 3 battery packs just like I did with that first Powerbook G4. Later 2 hours will likely become 3 or 4 and 4 hours will likely become 6 or 8... just like we see with ever-improving range of electric cars or any of the battery-based tech from Apple.
If you are wearing an Apple Watch, I have a watch that has a 10-year battery and recharges itself when out in the sun. It's 2024 and I'm sure I'm part of a majority here who thinks a Watch should last far longer than a day or two without having to be re-charged... especially when a cheap Timex can go years on a single battery. And yet, look at the wrist. There it is. You've adapted to its power limitations vs. a whole world of alternative watch tech that offers far more life between charges/battery replacements. Why? Because you wanted the watch enough to accept its relative limitations. This may be the same for some people.
Else, no one worried about this limitation should buy this product. Nobody has to buy any product. If a product does things you want, buy. If it doesn't, don't buy. I detest the rumored 2 hour limitation myself but I am excited at the potential of having access to a very large screen when traveling without the weight and packaging of any form of a physical screen as large. If that means dealing with limited battery life, I'll deal with it. The pros outweigh the cons to me.