"Always mystify, mislead, and surprise the enemy" - Stonewall Jackson.
In conflict, it pays to be unpredictable. For the same reason that unpredictability is useful when facing adversaries, predictability is useful when not. If you are predictable, it makes it easy for others to plan around you. Planning is generally easier if you can predict how everything will turn out. So any agent will find instrumental value in predictability. So you can provide value to others by being predictable.
Predictability is predictably valuable.
Take writing as an example. If a writer's output is like clock-work, you can reliably make time in your day to read their output. If you like their work, you may even subscribe to their patreon/substack/only-fans. This, in turn, means the writer knows they'll get one more view each time they publish, and one chunk of change each month. With enough readers, they can make a career out of it. You both get value from being predictable.
Whereas, if they regularly fail to publish, you probably won't dedicate time to checking in on them each day. You may even forget the writer existed. The writer, in turn, gets fewer steady views, reducing motivation. They may cease writing full time because the stress of not knowing if they'll earn enough money this month to pay the bills is too much.
This generalizes to other activities. If people know how you'll react, they can plan accordingly. You can shape their plans by choosing in what way you'll be predictable.
You can view a lot of human effort as about making things predictable. This isn't a new idea. Active inference talks about how humans want to reduce surprisal. Or how you can tell an ASI will predictably make the world look like its preferred state. Or consider utility maximization as description length minimization where utility maximization decomposes into reducing entropy and making the world look like what some model expects.
Until a couple of years ago, I didn't notice just how predictable we've made the world around us. Which, in turn, is a sign of how much humanity has optimized the Earth.
Consider houses. At the most basic level, we use them to protect ourselves against the weather. Four walls to keep out rain, sleet and hail. Windows to keep out hail, thunder and flashes lightning. Blessed boilers and air conditioners to shield us from sapping cold and burning heat. To be what the thrice-blasted weather won't be: predictable.
Or take a walk down the street. Observe the lamp posts, turning what was night into day. Note how you stomp heel-first across the flat, paved streets where once there was slippery mud, shifting sand and spiking stone. See the seething chaos of traffic turned orderly, cars instead of beasts, pavements for pedestrians and roads for vehicles, all pliantly conducted by lights of green, red and yellow.
Fly to a different city, step out and marvel at how similar it all is. Concrete, check, lamp-posts, check, traffic-lights, check. Supermarkets, light-switches, base-10, checkout and check-in. Every city must be centre because they breathe in and out seas of new people every day. Travellers need cities to be predictable.
Look at a book from basically anywhere in the world. What do you see? A shape longer than it is tall, white page and black text, matted cellulose fibres, a bar-code and ISBN, publication details amongst the first pages. Paperback, perhaps, or a hardback. Familiar, in short.
The world around us is amazingly predictable. And what is predictable, we take for granted. Of course, we have laws that apply basically equally to everyone. Obviously, I can have a coke and expect the same flavour every time. Clearly, I can expect gmail.com to look the same on any phone. Countless things like this I rarely notice throughout my day. When I consciously pay attention, I marvel at the routine nature of it all. It's almost made divine by the sheer human effort it represents.