You've made good points on this. My concern would be that police officers have an obligation to gather this information as it states in the article, and that they would lean on their powers to detain and arrest in order to coerce that information.

Let's run through a hypothetical. Routine traffic stop. Cop pulls out one of these cards and asks for your handles. You refuse, claim Miranda rights, or something similar. Cop says you, "match the description of a known suspect" (in a city as large as LA everyone matches a known suspect) and this is part of the ID process. "Of course, we can do a check using the computers at the station but you'll need to come with us until we confirm your ID ..."

Now, following through on that threat is an arrest, but under California law police have 48-hours to investigate before either charging you with a crime or releasing you. I doubt most officers would use the entire time, but letting someone stew for the afternoon in a drunk tank seems entirely within reason. During that time their car has been impounded and they're either missing work or missing time with their loved ones. Refusing to self identify could carry an effective fine in the hundreds of dollars, and that worries me.