It does offer a benefit when you own an A500 with a dead motherboard.
There would probably be a market for new replacement A4000D mobos too. I know I wouldn't mind one.
Why purchase a brand new 68030 accelerator to put into a 25 year old computer that could fail at any minute?
Plus, you're also missing the ZII slot (although getting anything to fit in that and be able to close the case should prove to ve interesting unless there is some sort of right angle adapter).
There's not much that can go wrong with an A500 motherboard besides the chips (which you're going to need for the new motherboard) or the sockets (which are easy to replace).
Why buy a whole new motherboard to populate it with 25 year old chips that could fail at any minute?
The side expansion connector on an A500 is pretty much ZII. If you want to use a ZII card on a A500, only a simple adapter is required. You're not going to fit any standard ZII card inside an A500 and still be able to close the case.