No, placing multiple orders at a high speed is not really that hard. It hardly takes any time in Nest. If the targets aren't too far (scalping), then no effort is required for squaring them off either. Being a bracket order, each executed order generates 2 orders, both which get squared off on reaching their target/SL. Therefore 300-400 orders is not much, it is actually like placing 100 odd orders.
Nothing about disclosing any strategy, but making a point here. Instead of trading 1000 shares in one trade, the orders are placed to trade 50 shares in each trade. There must be many traders following this, specially for high-beta scrips like JSPL, Relcap etc. The point I am making is that this kind of trader needs a more friendly platform.