I think it might depend on the type of digital ID you are referring to.

eBay require a driver's licence or proof of age card issued by your state's transport authority ( not the post office keypass) and for either of those shouldn't matter if physical or digital as the information contained should be the same, or a passport (or maybe immigration card??).

eBay won't accept myGov ID and probably not the new digital ID the government is in the process of introducing (although may in the future as seems to be specifically designed for online stuff!)