I can see what Chisora gains from this: a big payday and no pressure or expectation that he can win - but I can't work out what Fury's getting from it?
Maybe as
tonysingh says, it's simply a way to keep in shape and in the public eye, until a serious fight can be arranged. Is it true that Tyson and Derek are friends? If so, this could be seen as a benevolent gesture from Tyson - let me bash you up but you'll earn £XXX. Of course this theory would depend on Derek's share of the purse!
As someone who takes an interest but doesn't follow the sport very closely - is it the general consensus that Joshua is running scared and avoiding Fury like the plague - a second defeat after the Usyk fight could be a severe blow to his career.
I did hear or read someone arguing the opposite - that Fury is reluctant to fight AJ and therefore made the recent offer but with an impossibly short time frame - one week? - impossible for all the legal T's and I's in the contract to be crossed and dotted in time ... so that although it appeared he had made a genuine offer to AJ, there was no chance of it actually going ahead.
From what I've seen of both fighters, I would think Fury would run rings round AJ as well as bash him mercilessly. Tyson strikes me as an intelligent boxer and his upper body movement, for such a huge bloke, is incredible - ducking, weaving and generally avoiding getting bashed. Plus there's the aspect of Joshua's meltdown at the end of the Usyk fight - did that simply demonstrate his passion and desire to win, as I think he said, or does it indicate a mental fragility that could be a problem for him?
Noticed Tyson the other day referring to AJ as "the bodybuilder" - dunno if he'd always called AJ that, or if it's more recent, and a reminder of the fact that guys with the biggest muscles don't necessarily have the hardest punching power? I can't recall the science behind it, but it did make sense to me at the time