Majority of the manufacturer recommends the frothing pitcher because it's durable.
A standard stainless steel pitcher is durable, and it's an excellent conductor of heat.
Some other pitchers have a bigger diameter that's pointed into a smaller size at the tip. This unique design allows an eddy movement of milk before it becomes foam. Also, most of the pitchers in the market have a nozzle mouth for pouring the milk into the tank easily.