I don't have limit switches I have never reached end of travel for the work I do. After thinking about it I don't see why a high debounce would effect the homing switches.
If you read carefully, you may note that my comment was that if you share homing and limits in Mach. You may *think* that you don't have 'limit' switches, but that is simply a semantics argument that indicates you do not understand how Mach can handle 'home' switches.
Your assumption is theoretical and overly simplistic. You do not take deceleration into account in your calculations. In your case, you have the axis literally crawling up to the switch, but in any case, an axis is not going to stop instantly when the switch is triggered. The table weight (plus the vice, fixture and workpiece), the acceleration setting, the homing speed, 'cushion' between the switch and the hard stop, and finally the debounce setting all are part of the equation that predicts 'bang' or 'no bang'.
I would be interested to see a report that states an opto is 'more accurate' with higher voltage. Do you have a link to that?