It really shouldn't involve criticism at all. That's not the purpose of it, it's about externalising e.g. having that opportunity to look at the interaction when not involved directly in it, because when you're "in the moment" as a parent you are instinctively so focused on what's happening that it's difficult to be able to think about what's happening in a coherent way.
I think this is something that's true for all parent-child interaction.. I often think of the Health Visitor trying to talk to me over a screaming newborn and how I literally couldn't hear or process what she was saying because I was obviously totally engaged with the screaming. Also, sometimes it's too hard to explain an interaction.. so the purpose of video is to let the video do the talking, so that you don't have to verbalise it, you can just look at what's happening.
In our department, we do a lot of Adult-Child Interaction courses (practitioners come on some, parents on others) and it's been hotly debated in our team in terms of where it should go on a pathway because we know, as women too, that watching yourself on video is something that can be very uncomfortable even if you didn't have to also deal with the emotional impact of videos like these. Sometimes even if you're not at all feeling vulnerable just a shot of a double chin will override all other things you can see in a video!
In my experience, there are a group of people it is really helpful for.. who are generally happy to see themselves on video (and perhaps take a lot of video at home so are used to seeing themselves etc) and who can view the video appropriately. It's not for everyone.
I have also used video to demonstrate things like joint attention e.g. to point out things like social referencing of eye gaze e.g. as an education tool. I don't know if they do any of this in Early Bird as I am not Early Bird trained, but this can be a useful thing to do because it can be hard to explain in words!