Mainly for two reasons: To use it online to conduct transactions particularly Peer to peer mostly because it's far more reliable and more acceptable in person to person deals than PayPal, also as an investment to hold the funds and gain some profit from BTC volatility.
Wow thats greate can you share us some website where we can use my bitcoin too where to buy some random staff because bitcoin is more reliable where some stores are going to accepting bitcoin as a payment and person now are using bitcoin as a currency so that they can do investment
Online stores that accept bitcoin exists almost everywhere.
Newegg is probably the most popular yet (? still debatable) as one of the online markets that accept bitcoin payments.
I haven't used them personally since I don't use my bitcoin to buy stuff online.
But if you mean to actually buy
random staff, well, you can look for blacksmiths that accept bitcoin payments and I believe there may be a lot of them in the black market. Or just ask a local blacksmith and pay them with bitcoins. ==Double win.