It keeps you hydrated (drink water, tea [caffeine free in the afternoon] and coffee) and makes sure you don't sit at your desk for too long periods at a time.
I feel like a lot of these "life hack" kinda things are essentially just little pieces of entertainment/motivation you need to muster the initial energy needed to break a bad habit. Pomodoro sounds fun, it means tomato. It might let you fiddle with an app. You can track your progress and have fun charts to compare with potentially exciting results. And you have a story to tell people when they ask about your work.
The actual benefit of partitioning your day into exact 25 minute intervals is probably negligible, but while you're dealing with all this, you're actively working on being more productive and that alone has its benefits. It's probably a chicken-or-the-egg problem or even a plain old placebo effect, but it seems to work. Especially engineering types (as most people on hackernews) tend to have a problem accepting how convoluted psychology is, but sometimes just the decision to try to fix something fixes it.
Some time ago, I was making myself another cup at work late afternoon when my boss came, and he asked me if I'm staying longer today. I said no, I'm just staying for about one more tea. He asked me, jokingly, if I measure my work time in teas? I said, actually, I do - one tea takes me ~25-30 minutes to drink, so it's a pretty good unit of time...
Since quite some time, the bio on my Twitter is "This process emits code when Premium Cola is present on stdin."
If you're worried about bad chemicals that can't be washed off then the core would likely be poisoned as well because it's going through the skin.
For dirt, you can just wash it. Dirt is not harmful and doesn't penetrate the fruit.
About chemicals, a large part stays in the skin of fruits / vegetables, so it's always better to remove it when you're eating non organic food.
Guess people who want to try out standing desk may also need pair of a good & soft running shoes.