well to be completely blunt this isn't exactly a smart motto to live by, or at least the way I'm interpreting it makes it seem that way.
if you live with the mentality that your decisions are irrelevant because one day you will die, then by that logic you are permitting yourself to do anything you want. because you are basically saying, "I'm gonna die anyway, who cares if I fuck up." Here's a few examples why this is bad.
1. It's ok to commit crime
2. It's ok to be an asshole
3. It's ok to do wrong intentionally