That’s an interesting thread.. and I think that all of you are right as each answer represent one of many perspectives.
You can build a great site and get loads of traffic.. You can never know who is the person who clicked, what was he exactly looking for nor what exactly made him choose a free play or a sign up bonus. You can’t tell if his decision to make (or not to make) a deposit was impulsive or planned.
You can tell almost nothing about individuals and what made them click, join deposit, or even come to your site at first place.
You don’t even know where your visitor is from until his visit is over. You don’t know if he visited your site from the computer in his office in the middle of his day or from his home computer at night.
You can only focus on the marketing method you think you can do best and aim for the right target audience in general.
I use the free play offers on my sites to attract players and I get players who just use the free play and never deposit on one hand while on the other hand I see players that instantly deposit at casinos with no free promotions at all. I can’t tell you what made them sign up exactly.. But they did. So, aiming for free play promotions isn’t that bad.. you can never tell if will visit the casino and sign up because of another weekly promotion they like.
In other words,
The free play / no deposit offers are marketing method to get the player to visit the casino and “feel” it.
You can’t tell if the free play it self is the trigger for the deposit or any other reason.. but as you can see, free play offers are with us for a long time for a good reason.. no casino will run such a promo if it’s not successful for so long.
Good luck