since you can't change the input delay on those mice anyway, what does it matter to know the total input delay?
But you can see, that the faster mice have ~10ms lower delay than the beloved WMO(taking the IMO in this list for reference). :)
Could matter just so you can know how many frames it will take for the click to register with each mouse, but that's about it, yeah. If all you need is to compare the delays, it's more than enough.