> and you miss a part of the 'square' when you are turning (the arc of the curve is not a straight line)

This can heavily be mitigated through technique. If you walk straight and just turn? Yeah, the corner is missed. If you explicitly come to a stop and do your best to do a full 90-degree turn before moving? The only curve there is going to come from the shape of the blade, and is almost guaranteed to be a tighter curve than just walking and turning without stopping.

Yes, it takes longer. But if it's worth doing, it's worth doing right, even if it takes twice as long, no?