Half of my bikes have computers half don't. The highest mileage bikes have computers. I like to know how far and how long a trip is before I lead a ride for others. Sometimes I take others on a ride to the ferry and around an island, or a car ride a remote ride. It's nice to know if the dog needs to be fed and let out by someone else. Some of my friends want to know when we will be back from a ride.
Knowing how long it takes, and how far all my destinations are, means I know the same thing on a bike without a computer too. Having a couple of bikes with cadence means I know the rpm on bikes without cadence too.
Using the average speed tells me how long it will take me to get somewhere to meet someone. I like knowing how many miles I get out of tires, chains, wheels etc.
Sometimes I don't care about any of this. That's nice too.