I personally think that we as humans are always looking for someone or something that can protect us or help us because life is unpredictable and there are always hurdles we need to get through and destinations we want to reach.
I realize that a rabbit's foot is a controversial good luck charm because there is an animal rights aspect to it. I just want to point out that good luck charms exist for a reason. People started believing in them because they were probably faced with unfortunate or dangerous circumstances and needed a source of comfort and security.
I remember my dad had told me that if a traveler kept a rabbit's foot with them, they would have a safe journey and would reach their destination easily. This tradition probably came about a really long time ago when traveling was a difficult and dangerous thing to do. You might have faced hunger, illness or thieves along the way.
There might not be any scientific data about the effects of a good luck charm on a person. I think that simply believing in something can provide an immense amount of courage and comfort. For this reason, I think that most lucky charms, including rabbit's feet, have a positive influence on our psychology and just help us get through some of our fears and struggles. I also completely support the protection of animals and I think that rabbit's feet should be attained in a way that is not cruel to rabbits.