...are a good way to get loot boxes and other items you wouldn't normally get as easily!
You can die in certain /search and all /crime locations, and thus may lose all of your items and money in your wallet.
Life saver is a passive item. If you got any in your inventory, you won't die. Each would-be-death uses up one life saver.
If you can't get any life savers, stock up on apples instead and deposit your money frequently. Apples are an ACTIVE item that NEEDS TO BE USED in order to work. Using one saves you from losing your items in case of death for the next 24 hours.