The Min/Max is completely separate functionality from Auto Fit.
1- You don't run Auto Fit on all graphs. You don't run it on CPU Usage, GPU Load, Fan Speed, Core Clocks, CPU Temperature, GPU Temperature and all the major sensors.
2- Even if you did turn on Auto Fit, the values on the right are min max of the current graph and not all time. The functionality should be the same as min max in the main window. The one that has no graph and shows all sensors. If it was to show only the min max of the current graph, it would be of no use, because you can already see it in the graph.