Couple reasons, primarily to include more of our younger members that go from boat and not shore. This might work better for you too as now you can weigh in boat fish...
But I did keep the rule that the #1 prize is the top SHORE fish

AND to keep things even, if a boat fish is to beat a shore fish, it must do so by greater than 8 inches ....
Of Course there are so many prizes for the Junior Tournament, much more and in many cases better prizes, than for us old folks. You all are going to make out like BANDITS!