On what planet is it a worrying development?
Feature buys are predatory and scummy, online slots managed to be entertaining and enjoyable without them for many years, they're not an 'innovation' that offers the player anything positive, they're simply a way to plaster over the fact that some modern slots are fun-free zones that need a feature buy (and even a feature gamble) to make them even remotely engaging and interesting to play.
Everyone acknowledges that White Rabbit is essentially intolerable without the feature buy, so the problem here is that
BTG made a slot that's so dire to play that we feel compelled to buy features, and yet somehow some folks draw the conclusion that feature buys are a good thing and should be defended.
In essence, BTG created the 'problem', and then sell us the 'solution for 100x our normal stake, and somehow the UKGC are the bad guys for calling bullshit!