Question about SodaStream Power

Yes, it does.
The SodaStream needs the gas bottle for the "bubble formation" in the water. The electricity is needed for the automatic volume filling. Which - in my opinion - is very good and works very well.
You have a choice of 3 different CO2 levels. Few bubbles. Medium or a lot, according to your taste. And with the push of a button (not like the simpler models, where you determine the amount yourself by the duration of the press), the amount you want is automatically pumped in.