The biggest problem with cloaking is that it uses your action, which means you can't focus for defense.
Why do you need to focus for defense? Focusing increases your odds of rolling evades. Cloaking increases the number of defense dice you roll, increasing your odds of rolling evades.
With 3 defense dice, a focus token adds an an extra 3/4 evades, on average. Two additional defense dice add an extra 3/4 evades, on average.
There are tactical considerations to make, such as the fact that if you get a bonus defense die (from range for instance), you get an additional 1/4 evades from the focus that you wouldn't have gotten from the cloak. But cloaking is a defensive action overall just as potent as focusing or evading.