Other than the obvious difference in cost and simplicity of its configurability, I can only take wild guesses.
A hub plays a major role in a star topology which are still quite common today, latency through a hub is much lower than routers and switches. A hub can be used to distribute the backbone, if a switch malfunctions in a network, a major part of the network or the whole network will go down whereas if a hub crashes, the network will not crash with it.
As for diagnostics, if you plug in a network analyzer into a switch, you won't be able to see all the traffic whereas if you were using a hub, you can see all the traffic.
If I didn't give the answer you were looking for...PLEASE TELL ME!!! I WILL lose sleep over this and I treasure my sleep.