When you look at it logically you have a toy that is considerably less powerful than most airguns that don't have the same hoops as you can walk out to a shop right now and buy a semi auto air gun. They have the hoops purely because it looks like something more dangerous and its for airsoft and not another similar hobby like paintball. That doesn't really make any logical sense, a gun that is dangerous you can just buy but something that can't remotely kill someone requires proof you intend to use it in the appropriate places? These laws and the application of them wasn't really about actually making things safer, it was about being seen to do something. Its easy enough to make the argument that any reasonable skirmisher should be able to meet these requirements yearly and a new player doesn't have to wait very long at all. Just joining a rifle club with a police check can take 6-8 weeks these days so its not like 2 months is out of the question for an industry run scheme.
The hoop however distorts the retail market. Either making rental guns far more important and lucrative than they would otherwise be and causing the sale of a lot of two tone weapons as temporary replacements. You could argue the current system is very much advantageous to the retailers because they often get to sell two guns purely because of UKARA and how they interpreted the law. I don't think its a really arduous hoops, its mostly impacting on new people coming into the hobby and making it more expensive for them to do so by about £100 where I am (either the gun is ~£100 or rental at £30 a game). Having to lump down rental money for 2 months or buy a beginners two tone isn't awful but its also increasing revenue to the airsoft stores and sites.
Then what wolfarmouries does is allow you to buy a RIF from them and they will bring it along to any game you prebook, so you can avoid the rentals and still use your gun in games. That is great, its also a wonderful way to ensure all players at Bunker 51 have to buy their gun from them, helping to make them much cheaper overall than their competitors even if they are charge more for the gun itself. That is just another little application of the implications of this minor hoop that makes stores that run sites and run a similar scheme get to increase their yearly sales a little even if they are more expensive than the others.
Its not that the hoops are really bad, I don't think its reasonable to argue against the 2 month minimum or the 3 game yearly limit they are in my mind perfectly reasonable measures. But we also have to recognise that some sites charge for getting the UKARA form stamped for a yearly membership to their site as well, just another way in which UKARA is used. We do have to recognise it distorts the retail and site market and its being used to fleece us of more cash, and puts a barrier in the way for new players who are disadvantaged by it.