Almost all the PCBs I've seen for now are right angle. But I think such acute angles are not safe for handing, even when installed on the products, it may do some bad to the wires connecting the boards. But why the chamfered corners are so rarely? For cost reason? Or there are other merits using right angles?
PCBs are not knives. An edge won't cut you. If you have wires that can rub against the edge of the board, that's just bad system design, and you deserve whatever ill effects come from it. Chamfering would be a solution looking for a problem. If it's that big of a deal, V groove rather than route the edges. That gives a more angled edge. The better solution is better system engineering.