I am not against 1 on 1's, but making that a regularly scheduled thing as if that adds value is kind of what I am arguing against. If people don't feel comfortable voicing something unless it is in private to their manager, that suggests to me two things - the manager/leadership is not fostering a collaborative environment, or the person needs to work on that (with the assistance/support of their manager), which I see as a manager's primary value gain, empowering their employees.

Managing via 1 on 1's sounds (to me) like a complete waste of everyone's time and a little bit toxic. It also can create an environment encouraging people to go around each other and backstab rather than collaborate. I have been in a lead position before, I'd be very concerned and probably have a series of chats with any dev that sat on something like a blocker until we spoke one on one, or only felt comfortable speaking one on one.

Some things do need to be spoken privately, and they should feel comfortable doing so/scheduling it, but a regularly scheduled thing as a way of managing, unless I am completely misunderstanding GP comment, is crazy to me. Of course I am speaking strictly manager/lead -> developer. A manager managing managers is probably quite a bit different and does require scheduling 1 on 1's regularly to align and adjust, but I wouldn't really know, because I've never been in that role.