There is little doubt in my mind that the exchange rate should appreciate. This is part of the necessary process of bringing about the real transfer of resources (a current account deficit) which is the counterpart of the financial flows. But, to the extent that the exchange rate may well overshoot in this process, intervention is a legitimate policy option.
We all know the constraints and difficulties with this. In particular, it is fiscally very expensive. But it can be a useful instrument in the toolbox, for moderate, occasional and discrete use.