Basic insight into what your device is doing, and which app is doing what.
Lets you build intuition about what is normal vs abnormal. And it's also essential for letting you perceive which apps are bad citizens (and good citizens). Try one of these tools out for a month and you catch all sorts of random things.
Funnily enough, the computer's fan used to perform part of this role. But that has increasingly gone away as laptops become increasingly silent.
Once I randomly opened Activity Monitor on my M1 Macbook only to find that vim was using 100% of a CPU core, and the timer said it had been in this state for days! It wasn't even in the foreground of any terminal tab. Just in a spinloop in the background doing who knows what. And it might have stayed like this for a year until I'm forced to reset the computer for an update.
Another example that you might find more compelling is when your computer's network jumps to 5MB/s. It should always be explainable.
Lets you build intuition about what is normal vs abnormal. And it's also essential for letting you perceive which apps are bad citizens (and good citizens). Try one of these tools out for a month and you catch all sorts of random things.
Funnily enough, the computer's fan used to perform part of this role. But that has increasingly gone away as laptops become increasingly silent.
Once I randomly opened Activity Monitor on my M1 Macbook only to find that vim was using 100% of a CPU core, and the timer said it had been in this state for days! It wasn't even in the foreground of any terminal tab. Just in a spinloop in the background doing who knows what. And it might have stayed like this for a year until I'm forced to reset the computer for an update.
Another example that you might find more compelling is when your computer's network jumps to 5MB/s. It should always be explainable.