Quite honestly, I never found the doctors here all that great about marking our vaccine records. For my first child, I know they all got recorded up through the 4 year booster, but after that, nothing has been marked. Our youngest, I think they only marked the first few shots, and nothing after that. So their cards wouldn't be accurate at all.
Also, myself personally, even on personal medical records, they weren't great. So, I had the Whooping Cough booster when DD was born, because that was right around the time cases were starting to rise again; they had realized oh crap, these don't actually give life long immunity. I had also received a tetanus booster in the ER a couple years before that.
So that's fine. It was coming up near the time when I knew my tetanus would be due, but I was pretty sure the shot I had when DD was born contained tetanus as well, but I wasn't 100% sure. So I called my doctor's office to find out thinking it would be easily found, noted on my digital records. Well, let me tell you, I was wrong. They had to go digging back through years of paper records to find out what I had actually received and when. It took a few days before I ever heard back.
So, while on one hand yes, I dislike requiring the vaccine, I do like the idea of a digital record, that is easily accessed anywhere, anytime.