If they does have smartphone and hacked logs plus does knows PIN, yes....might use.When you get the card how do you log in to see it or is it a password? Does it need a phone with biometrics, like fingerprints or face scan?
I wonder if your phone is stolen is your ID usable by a gang? Then what? You need another phone or PC to call up and get the ID suspended? It seems a phone is more likely to get lost than a passport or driving licence.
But if on holiday a digital ID could be easier if you lost your passport and need to go to an embassy.
If it can be used to prove right to work or study, meaning people don't have to pay to update their ID as often, that's good and will benefit many, particularly those on the breadline or who don't have the necessary professional, non-familial contacts to get a first passport so quickly (since the first one requires co-signing by someone who's known you for several years, isn't family and is from a list of particular professions). Removing barriers to work and study for those who have the legal right, ability and willingness to do so is always good for the economy, society and social mobility. "Oh, you want to do a course, but have an expired British passport, a driving licence with a recent old address, extensive tax and address records with other government departments, copies of bills, can take photos of yourself with your passport...no, we only accept a photo of a valid passport, because some senior civil servant said so". Nonsensical bureaucracy.
However to get place as student or normal job with ID card alone definitely isn't enough.
No, ID card in U.K or EU or EEZ can't 100% replace physical passport ... in some cases it is mandatory to have...yes, physical passport and in person. Maybe also 2 nd document and other documents too.