Many people who play in casinos a lot may argue that an online casino is not as good as a real one. This could be very true but not many people have access to a casino and this is why the online casino is such a popular thing. Also when you are in a real casino you have to interact with real people and some would rather that no one knew exactly how much money they were gambling.
You may also feel that a real casino is more expensive, maybe the minimum bets are higher or you will be tempted to buy drinks at the bar and perhaps food and this will all add to the cost of the evening. Really the two things are quite different but they both have a principle where you can pay to play games and you might win a prize. The games tend to be similar, but playing with a computer is very different to playing in real life unless you play slot machines. Slot machines are computers anyway so whether you play in a casino or online there is not a lot of difference.
The only thing being that the sound effects may not be so good on a computer because you will never hear real money falling out of the machine. But if you have never been to a casino, then playing on line is the closest thing you will get to going. If you cannot get a to a casino regularly then playing on line could be a great substitute as well. The games are similar and you still have a chance of winning money, which for some people is the main attraction. If you have never tried an online casino, the only way to find out what it is really like is to have a go for yourself.