Wrong explanation to give.
The decision to put money in a fixed deposit is not an 'investment'
by any means, shape, or form. There is no 'investment objective,
and rationale of investment' , as you put it.
It is not a way to 'accumulate emergency cash' either. Firstly,
there is no accumulation. The inflation rate is practically
negating any accumulation from the lousy interest rate. What
accumulation exactly are you talking about? You may even see your
money dwindle. Secondly, it is in no way a method to accumulate
'emergency' cash, as you put it again. In case of an emergency, the
deposit cannot be retrieved or liquidated quickly.
Cash flow? The cash flow sucks. Obvious.
'Of course, there are other means of investment.' For this
sentence, again, a deposit is not exactly an investment. However
you are right in the respect that there are other options to put
your money. If you put money in a fixed deposit, you are letting
your bank make money from you. Fixed deposit is a product from a
producer or a seller interested to make profits for
themselves.