Suppose you have a member named "x." Someday, you might want to stop storing x, and instead make it a calculated value. At which point you'll need a method. Or, when setting x, you may someday want to increment a counter, or transform the input data, or take some other action. Again, you'll need a method.
Yes, it's very easy to add an accessor later. But then you'll most likely have to edit every line of code that accessed the now-defunct member variable. Your IDE may make this easy, but I'd still prefer not to have to do it.
That's not to say writing accessors is always the best choice. I'm just saying there can be good reasons to do it. Like all things in software engineering, there's no one-size-fits-all rule about this. Notch is right about the bloat accessors create, so you have to weight the advantages and disadvantages yourself in each case.