Why is TPM enabled/activated by default on coreboot+SeaBIOS L14?

Correct me if I’m wrong, but the sole purpose of TPM on Librem laptops seems to be to facilitate Pureboot.

Then why do L14s without Pureboot (i.e. with coreboot+SeaBIOS) come with TPM “Enabled and active”?

When I enter TPM configuration it shows me 4 options:
d. Disable the TPM
v. Deactivate the TPM
s. Allow installation of an owner
c. Clear ownership

Can someone please explain the difference between “disable” and “deactivate” here?