Yeah that's absolutely true if a casino is paying you to make a review of there casino then you will have play review by there rules because I do not think that a casino will pay you for a review and allow you to write what you feel even if it is good or bad about the casino, they will want to pattern the way you should write for you so that it will be in the favour of the casino at the end of the day. Paid casino reviews are not supposed to be regarded as the actual review of the casino but the question is how do you know which is a sponsored casino review and which is a genuine casino review because it can be misleading at the end of the day.
Please this not always true because some platform care more about their integrity than the money they are paid to review the casino. They understand the consequence of writing positive and nice things about a scam site so despite the money, they will try to remain as neutral as possible because that is how they will be taken seriously. A review site that is only interested in the money and not on delivering objective review will become a laughing stock that will never be taken seriously.
When reviewing a site it's might not be easy to detect if the reviews where paid review or not depending on individuals, registering with the casino give the client the opportunity to observe every thing he needs to know about the casino but before that it's very important to read the TOS before making any decisions.
As a new or existing casino in the market they need to build trust so that more people will patronize them, so good reviews creates a an enabling and satisfactory mindset for the client to feel secure.