Randomness makes for better immersion. For example, let’s say that each tree has a fixed health count of 100, and each axe strike takes 25 points off a tree’s health. This task will soon become predictable, and therefore, boring. Even if you give the trees a health range of 76 to 100, any given tree will be four strikes away from falling. But trying a smaller range of, say, 75 to 76 provides a greater variety of gameplay outcomes, as a tree will take between three and four hits to fall.
Another way to make this scenario interesting is to indicate health changes through clear visual cues instead of health bars. Doing this will allow the player to learn, through gameplay, approximately how many axe swings it’ll take for a tree to fall. Visual cues add some limited unpredictability that can be balanced and adjusted for the target gameplay. Using the Random class instead of a fixed value enables you to transform a monotonous task into a fun one.
To expand on this example, you could choose to remove a random value between 15 and 25 health points for each axe swing. Doing this makes it so that players can’t easily predict how many swings it’ll take to cut down a tree. They’ll need to rely more closely on visual clues to gauge when a tree will fall; clues like the size of chunks flying from the tree or cracks forming up the trunk, branches falling, sound effects, and so on.
They won’t know precisely when each tree will fall, but over time, as players chop down more trees, they can make educated guesses, ultimately improving their chances at survival.