>Or a second transaction layer, like a bank or VISA?
* They don't transact bitcoin.
* They don't transact your (non)bitcoin in a decentralized way. They alone run the software and are in control of changes and restrictions, including who you're allowed to send to.
* You don't hold the private keys to your (non)bitcoin when it's a bank or VISA or Paypal. They own it for you. They can lock your account and maybe give you the privilege of putting yourself through some asinine process to regain access to it.
The lightning network is a "second layer" that still is decentralized and puts users in control of their own funds.