A bit, as posted in this blog, but for most part having physical unlimited access to a device it's game over. Hence why encrypting your sensitive data should be the norm (I am aware that is not the norm, not by far)
Sure, it's just that the only situation I see a BIOS password making sense is in the presence of some intrusion-detection mechanism that would perform some kind of destruction/lockdown/alarm so that attempting to bypass it would not be without consequences.
Depends on your definition of encrypted I suppose. Many laptop SSDs are technically encrypted by default, but unless otherwise specified use a default key to unlock the drive.
Sure, they are still not encrypted in any meaningful sense by default, but the barrier to entry is quite far removed by not requiring a long process to enable it. A process which sometimes would require reinstallation, something an average person would likely not bother with.
While installing macOS Catalina the user gets prompted to activate this encryption, providing the system has a disk that supports that kind of full disk encryption I mentioned above.
