Yes your queues will be a bit longer, but at the benefit of having more people enjoy this exclusive wait? It's still extra time in park that no other normal, inferior peasant guests have.
You say that guests who book online already have the benefits of discounted entry and no queueing so that's enough. Well I could say the same about annual pass holders. Yes, it shows a reliable, valued customer, but you do get discounted food, hotel, merch. blar blar blar as well as ERT. Also, the discount isn't exactly the best incentive going seeing as couchers enable much cheaper prices anyway.
I mean, if every day were as busy as, say, a Halloween day or summer day then I could see your point. But its noit. a guest who has just bought their tickets online thinking they were getting a better deal then arriving at the gates to find a 10, 5 or no minute wait for the ticket booths, they wouldn't feel as valued as an officially pre-cooked person should.
I'm also glad that they have reverted back to having thrill rides on the menu for ERT, as last year it was pretty much all family rides.