Section 8.6.b Release of Product has a requirement for "traceability to the person(s) authorizing the release".
Some industries, such as aerospace, require when acceptance authority media (stamps, electronic signatures, passwords) are used in place of signatures, "the organization shall establish controls for the media" (8.5.2). One argument to keep physical signatures is if the company does not have (and chooses not to invest in) adequate controls to prevent workers making computer entries using another worker's identity.
I can relate to the desire to retain physical signatures. I am old school and for contemporary records, I prefer paper. As a pre-Gen X quality person, I personally feel a psychological pause whenever I am asked to sign my name on a quality record and put my reputation and good name on the line. The act of a physical signature feels like a making promise, less anonymous, compared to entering a employee number or a string of random characters in a computer password.
The origin of a "traveler" was a paper record which travels with the product through steps in the production factory. At points in the production sequence, there may arise a legitimate question whether a previous operation was completed on this particular part or lot of material, and what was the outcome. With a paper traveler, the person with the question only has to glance at the traveler to find the answer. If instead, an employee must leave the plant floor to find a computer terminal and login to determine the status of a part/lot, that loss of convenience comes at a cost. I realize Industry 4.0 brings modern technological solutions to this scenario, but many enterprises lag behind in implementation of instantaneous mobile electronic access. Sometimes, for good reason, such as security concerns or cost to implement. These laggard companies still have to comply with 8.5.1 Control of Production and Service Provision.
Paper also affords a place to record important contemporary details, or even a sketch, where the need to add comments was not foreseen by the ERP programmer. There may have been a machine fault or other uncommon occurrence that deserves be recorded. Recording comments on a tablet without a keyboard is not the same as writing it on paper, in my opinion. Recording notes in a general comments field on a different tab below the entry screen is no guarantee that the important note will be seen by subsequent workers in the production sequence. These are a few reasons I think justify continued use of a physical traveler with signatures.