I'm sure fuel rod feels they have the critical mass to start charging. Probably can't quite keep up with demand for the swaps, or the service life of the battery is now approaching end of life, so they need to add to their swap inventory. We have 2, Disney was the prime reason for the purchase. We can still cycle them in, and charge at the room. Haven't HAD to swap much, as we could get through the day with what we had and charge at night. Sometimes we did swap because it was an option, and it just made sense to swap out as the opportunity was there.
I will say my samsung s9+ handles a full day of park stuff, where my s7, just couldn't last half a day. So I think in general phone battery life is improving across the board.