The main reason is, of course, the possibility of easy money. In my opinion, the advantages of online are as follows:
1. Comfort. A person is in familiar conditions, not in a hurry and can play at any time available to him. Also, he does not have to adapt to the habits of partners.
2. Privacy. When winning a major championship, there are always fears that criminals will find out about it. It is much easier to remain anonymous on the Internet than in a casino.
For people who do not like to make quick decisions, poker on the Internet is an ideal option, because you do not need to adjust to the pace of partners. There is an incredible number of tables with different players, where you can play in several rooms.