Interesting, not much cubic capacity, lift height (at least the one the op listed) and you have to always look backwards. Definite drawbacks, but probably the cheapest way short of a wheel barrow and shovel to move some product.
Some of the bigger units deal with the lift height, but at how close of a cost to a FEL?
Looks like you would need some front counter weights, that big one shown in the last videos sure wants to "front" up with just snow, I would imagine what would happen if it had a full load of gravel in the bucket.
Personally it would have limited uses to me, as the drawbacks would become very wearing very quickly in my opinion. But then it probably is better than a shovel / wheel barrow combo, but far short of a true loader. (and far cheaper)
David