The fact that you have to manually type in `apt-get update` (or similar) means it's not automatic. You have full control over when the update takes place, and which packages get updated.
So in practical terms, my experience is that vanishingly few people will behave differently than an auto-update system would behave, except in rare occasions like a malicious update making the headlines. We definitely need a solution for rejecting malicious updates, but I feel backing away from auto updates throws the baby out with the bathwater and would be a net-negative change for the industry and for users.
I don't envy Chrome leadership's decision or having that problem to solve.
Without automatic updates, you might be more inclined to put off a patch which turns out to be urgent. Or you might be more likely to lose track of which patches have been applied across your various systems.