All the washing of things you have to use in intermediate steps really adds up. And unless you eat chicken breast for every non-breakfast meal, 10 cooked chicken breasts will get gross in the fridge pretty quickly, so you'll probably want to do something like 3 breasts at a time if you're only eating one meal with chicken breasts per day. This means doing meal prep twice in the week, as opposed to once. If you don't refrigerate them, then you have to wait for the breasts to thaw, which is time I don't want to spend every day, multiple times a day potentially.
I have a busy schedule, and every hour counts some weeks, so the time saved after buying canned chicken breast really adds up.
The chicken does come out moist and tastes awesome, but that goes for the outside as well which I don't mind that much, but you can also toss it on the grill for like 20-30s a side after it's done if you want nice grill marks and a little crispier outside.