Varying my environment and the way I do things helps a lot with my productivity. Going offline is an opportunity to look at things from a different angle: different support, different perspective.
The simplest solution is often the best, and many key activities don't require an Internet connection. Carrying a laptop or a smartphone or a tablet is a constraint: I need an electric plug to load the battery, a place with shadows to look at my screen without hurting my eyes, and a flat surface to correctly ventilate the hardware.
Spending more time offline is also great for my mental health. Leaving my computer at home is a great way to experience more of what my life as a digital nomad has to offer: enjoying a book on my e-reader while sitting on a park bench, writing a few words in a bar sipping beers, or brainstorming new product ideas and designs at the library.
Going offline is particularly suitable for mental sketching - ideation, free-writing, planning, software requirement elicitation, high-level design, etc. - but also to increase mindfulness through reading, daydreaming, journaling, or traditional meditation. The possibilities are many when you think about it.
There is no limit to the digital world, and some might say the physical world is only getting smaller. Sometimes, staring at a screen feels too much like work. Most of my professional tasks necessitate a computer, but balance is needed. A pen, a piece of paper, a book, and a conversation with a stranger, a friend, or a lover, can be more powerful than any website:
"He had collected over the years thousands of bits of stories, characters, lessons on life, laws of psychology, that he slowly pieced together in the novel, like tiles of a mosaic. He could not foresee the end."
- Robert Greene on Marcel Proust, in the book Mastery