Development of gambling sites takes a lot of effort including costs associated with hosting and domain renewals. It is not the easiest job trying to keep up with the changes in the search engines when you must do upgrades. Examples of that would be mobile friendly which is a good idea plus many other structural factors within the coding. Once you get your basic sites configured properly and you have provided great contents, will you rank? Not always, you are at the mercy of the engines and if/when you do rank you have competitors knocking you down by doing negative things to your site. Overall it does make it quite difficult to make money from online casinos anymore.
The webmasters of the free gambling casino’s know that most online visitors will, at one stage or the other of their playing life, want to earn money like many others do. However these visitors do not want to risk their money on new and strange casino games. To give such online players an opportunity to know more about the games they will find in the paid section, the webmasters provide them an option to check it out in the free gambling sites.