In tissue advertising, you are given a bored and immobilized consumer-base who can spare more time to read and contemplate the messages you tell them. Tissue paper is more useful than brochures and flyers. When given in packs, people keep them either for future use or to pass to others for their use. This gives them mobility and visibility unlike any other.
If people see something relevant to their basic needs, they often remember things associated to those. Giving them something to read on something they often use can be one of the best ways to encourage brand exposure and recall.
It’s an ingenious way to “wipe” the competition away.