I know many people who don't want to have a touring plan laid out before they go to WDW. They think a touring plan means they will spend their vacation watching the clock and rushing from ride to ride to restaurant to meet and greet. So they show up with no plans and are frustrated to find all the rides they want to ride have long lines and they can't get into the restaurant they heard so much about.
My experience is that having a touring plans means everyone has a great trip. I schedule rides, but allow lots of wiggle room for "smelling the flowers". Also, taking those necessary pictures in front of the castle, browsing in the stores, and eating a Mickey-shaped treat.
By arrving before "rope drop", we beat the crowds to the headliner rides. By making wise FastPass Plus (FP+) reservations at midnight on my 60th day before arrival, I can spend my late morning time redeeming my FP+, using the time between for rides with shorter queues.
I have only used the Advanced Dining Reservation option once, but it let me eat at a popular restaurant on a busy night. :-)
For those who go to the parks frequently, this isn't really a big deal. If you don't get to ride Space Mountain this trip, you know you will be back soon to try again.
But for families who only get to Walt Disney World once and a while (or only once!), spending the time beforehand to put together a touring plan is a great investment in your vacation.