I believe cash is also decentralized until you have to much to store and it becomes complicated and risky to keep it under your bed. Keeping your bitcoins insid

I believe cash is also decentralized until you have to much to store and it becomes complicated and risky to keep it under your bed. Keeping your bitcoins inside your computer comes to a cost of security and maintenance with the risk of losing them or getting robbed... Giving them to a bank you trust is the solution if you can't do that on your own.