I am not fan of gambling at all but when I found out that there is a website which I can play Dice and just use Bitcoin for my funds I got hook in playing it so yes I think online casinos or gambling site that use bitcoin can attract bitcoin users. At first they will only purchase bitcoin for their gambling habit but they will eventually realize that bitcoin is not just made for that but its an investment and also a very inportant technology sonthey will start buying and holding bitcoin.