Now that is a good question.
These days Cell Phones have your "life" on it, your apps, that you use for budgeting, emails, etc.
If your insurance covers this when you have theft of identity
Also phones are worth a lot of money, almost as much as a laptop or musical instrument.
These phones can be fragile or malfunction, it would be handy to be able to have this fixed quickly and with not so much out of pocket expenses.
It depends on how much you value your phone, or how much of a pain it is going to be when you don't have it.
I used to think the same way about pet insurance until I got my kitty, and she was unwell.