Immutability is certainly tempting for certain kinds of data. Does it handle use-cases where data needs to be deleted though? i.e., privacy compliance.
It looks like they call that excision, which leaves behind a breadcrumb saying something was deleted and which can't itself be deleted.
Temporality in general becomes super handy if you have something like reports that need to be consistent across time. Or if you want to ask questions about the past. Or questions about the future without affecting the present.