There’s is no greater remedy of the body than abstaining from food and water. It is the only general cure-all for all chronic lifestyle diseases. Well, I suppose that’s not entirely true, the body is of course the one doing the curing, abstention is just a messenger to notify the cells that its time to get rid of waste and rejuvenate to optimal efficiency, which is as good a definition of health as I’ve heard.
What do you mean by “crucial”? There are plenty of healthy people who have never dry fasted a day in their lives. Dry fasting is a tool, so is regularly using a sauna, so is cold exposure, so is resistance training, so are medicinal mushrooms, etc … all have related subreddits.