Every people's investment preferences are different. Some people but shares or choose cash, others make investment on bitcoin. I admit, bitcoin price is falling down. Everyone thinks its price and value will increase again. So, they want to take their share form it.
People are buying and still buy bitcoin because we believe that bitcoin can help us in many ways. Bitcoin helps us get extra income gain profit through investments. So even if the bitcoin price now is lower than in yhe previous, we still buy because we believe in it.