It's not an exact copy of all the data. For example random downloaded files don't get backed up and restored unless you migrate from an old device[0]. It would be nice to be able to do a full device local backup and restore.

[0]https://support.google.com/android/answer/6193424?hl=en

In my experience the backup is very limited and most app data is lost, specially annoying are banking apps that require you to go to a physical bank branch in order to re-pair your restored phone and restore full access to your bank account.

Banking apps willfully prevent backups on both platforms, it's not something you'll get from the phone.

Someone put "prevent backups" on banks security audit checklist and that's that.

My main issue, at least here where I live, is that you can only have a single phone paired to your bank account. If anything happens to your phone, that's it, you are locked out of accessing your bank acc. You used to be able to access your bank account from a telephone call (sure, very arctic and insecure nowadays) or from the bank website without requiring the phone app to authenticate.

Had they provided a second form of access, independently of a single phone, I would be more than fine with it.

It's not just banking apps, it's almost every app that isn't a first-party Google product. You also lose all of your files, but those can at least be backed up manually by copying them over USB.

I’ve never heard of that. Is it outside the US?

Yes, it's tied to your Google Account

iPhone can be backed up to a Mac or PC.

Even then, some apps "know better" and are not backed up. Signal is one of the bigger offenders on this front (despite there being options for E2E encrypted / on-site backup in iOS).

Signal has its own backup feature that will backup to a file on your device on Android as well.

Settings -> Chats -> Chat backups

Signal for iOS does not allow backup. And the developers said they would remove it for Android probably. But it was years ago.