Re: Why did they do it?
"Remind me again why, exactly, the manufacturer of my home so-called "security" equipment needs to have a feed from that equipment?"
Two reasons I can think of.
1) To minimise size and therefore cost of manufacture. The video needs to be stored somewhere. A locally hosted device (probably a separate box somewhere in the home, as bunging a HDD or SSD in the doorbell would make it rather larger) costs money. Much cheaper to bung in a Wifi chipset then shove the video on to a server that you probably already own or rent.
2) Monetization. You have access to terabytes of data showing people coming and going that could potentially be worth something.
Neither is good from a user point of view.. Personally, I would like to see any device that offers any kind of home security or surveillance to at least offer the choice of storing data on a box locally, with the option to upload it to a cloud. I'd like to see this happen even if it means I lose the convenience of accessing the video from my doorbell or CCTV system from outside the house, or via an app.
I don't have a smart doorbell, because I can't see the point. If I am not in the house, what, really is the point of me being able to answer the doorbell? Even if I get a delivery, unless I have just popped to the neighbours, the delivery driver won't be there by the time I get home (even if he or she was, I could just open the door). I might be interested in the video doorbell aspect, but I think any data stored by the system should stay local. Same with CCTV.