Getting the tech adopted might be difficult (like you say some judges may not see the point of it) but the PKI doesn’t have to be super complicated…
Having different authorities provide signatures for different types of documents may or may not be needed, in theory it is more secure, but just checking the domain name suffix should be a good start. And every tech literate person has a general idea how to tell “valid” domain names from phishing sites, so the scheme translates well