Last week we were on a Dive Boat in Cuban waters - Jardines de la Reina. The boat had no Wi-Fi or Satellite and there were no cell towers in range. Even if there were, we would have needed a Cuban SIM card to get service. So, we had no connectivity whatsoever, we were in the dark, off-grid, for the entire week. We were expecting this so we prepared as much as we could, we still took our phones
because they are our cameras, our ebook readers, and all our documents are on them.
You might not find yourself in situations quite this extreme, but if you travel, or even if you're in a hurricane where power (and Wi-Fi) goes off, you will at times find yourself without your normal connectivity.