BTC are "commodities". People buy/sell/hold gold, silver, and other commodities, and have for decades.

There are price swings, and the swing is on the upside right now.

I mostly got into AltCoins because at the three September porn trade shows, Amsterdam, Berlin and Prague, it was a topic that was constantly on the agenda.

I put my Wallet QR Code on my shopping cart checkout pages. It is possible that there are customers wanting to spend recent BitCoin riches on porn... or maybe I'm getting ready now for future acceptance globally.

Some people Buy and Sell Coins, some "trade" Coins at a substantial "discount" rate. There are "mining sites" that need to be very carefully checked out for Ponzi schemes. There are ICOs, Initial Coin Offerings, for new Coins; if you buy during the ICO, you get a bonus fraction of a Coin.