This is purely conjecture on my part but if I were a gambling man I’d say that this is an attempt to insulate a potential issue with a bad batch of cells. A bad battery charge that forces you onto another phone is probably better than a repeat of the Samsung battery issue. In essence it’s a sneaky recall without the bad press.
I can’t really come up with another reason that they’d be doing that.
It might be worth looking into what the affected serial # range is. From what I’ve seen / read (anecdotal) batteries are under the most stress when fast charging: you could reduce risk using lower wattage chargers in all likelihood… but I’d definitely explore all your options.