Mineflails are pretty useful if you are insistent on crushing infantry.
The mineflail increases the crushing radius of the Sherman, but the infantry don't recognise the extra range on the Sherman. This means that if you go full speed into infantry, theres a good chance they wont dodge in time.
You can also place your Sherman directly next to an infantryman, then rotate into the squad, and nudge forwards. This insta-gibs the infantryman in question, as he will physically be 'In' the extended crushing radius, but movement is required for crushing to actually happen.
Tbh, it's only really useful for detonating mines if you know that they have been placed in advance.
Most important part to note here is that you do not need to flail to be turned on for the extension to count or be active.
