It would let me know if there is something unusual even if I am out of sight... I think this alone is worth installing. I have installed it in both of the cars I own.
But don't be overconfident, do daily test runs, etc. to check whether the alarm goes off normally? Do you receive notifications on your phone? If the system does not notify you of an abnormality, you should check the status of the system.
I had a problem before where no notifications were sent out, and when I contacted support, they kindly told me how to deal with the problem, which was a relief, but I feel that checks should be carried out to avoid missing something that is not working...