What makes TPM more secure than a good old passkey for Full Disk Encryption?

All you need to do is press the power button and the computer is decrypted automatically... What's the point? I get if someone steals the computer it's helpful and it prevents a hacker from using the sethc exploit but surely it isn't difficult to bypass the windows lock screen to steal data? You might need specialized tools or something but it is possible no? Isn't a password for FDE the way to go in terms of security? I get its …

disk encryption encryption full disk encryption old passkey privacy tpm