It's their choice anyway, to buy BTC. I can see some reasons like, they arewilling to spend money just to add butcoin in their savings and then they are going to sell it soon as the bitcoin price increases.
When you see that something is profitable and you can make handsome money from there you will definitely invest there. That is doing all the people. I know that bitcoin is profitable investment and I will buy some bitcoin when I have money for investment. Although some mishaps and corrections are also involved but on the whole it is profitable.