Quote ="Scarlet Pimpernell"They have already thought of a benefit in defence by giving away another six usually after the first tackle to allow them to reset their defensive line by laying on. This is appearing to be the case regardless of the area of play but think of the benefit if you are defending your line knowing that you won’t face a penalty and just lose one tackle.'"
You're right, but I think the benefits overall outweigh the negatives.
I like the rule, because I think it's being used where the laying-on isn't quite enough for a penalty but obviously slowing it down. You don't want refs blowing for penalties all the time but a quick punishment for being too slow seems to work.