1) The pi 400 is not exactly abundant and it won't be easy to buy large quantities. When I said they were easy to get, I meant you could e.g. put yourself on adafruit's waiting list and get a notification fairly quickly that allows you to snag a unit, or maybe 2 units, but either way it is a low limit. Even if you are obnoxious and go buy up all you can find night and day, it still won't be a lot on the scale of things.
2) the packaging with the keyboard actually is fairly compact. I'm going to use mine like I would normally used a boxed 4b (i.e. as sort of a home server tucked out of sight) but am not going to try taking the board out of the case. It looks like a small keyboard in a normal keyboard enclosure and doesn't take that much space. It isn't really that visible that there is a computer inside.
2) the packaging with the keyboard actually is fairly compact. I'm going to use mine like I would normally used a boxed 4b (i.e. as sort of a home server tucked out of sight) but am not going to try taking the board out of the case. It looks like a small keyboard in a normal keyboard enclosure and doesn't take that much space. It isn't really that visible that there is a computer inside.