Keychain Access on Mac but not iOS

So I know that with iOS 18 and MacOS 15 Sequoia, Apple introduced a new app called Passwords. It replaced the Mac app Keychain Access. In Sequoia, Keychain Access is still around, but if you search for it in Spotlight and try to open it, it says Manage Your Passwords in the New Passwords App. My question is why Keychain Access is still on MacOS if they have the Passwords app, and if it's so necessary on Mac, then why isn't it also on iOS? Can we remove Keychain Access Apple?