Nothing wrong if there are people who will follow them without money involved. But the fact that they will soon ask for money from their users is already enough reason why people shouldn't follow them. Even though they are a legit provider of signals and really have experienced has it, that kind of service has a bad reputation here in the forum and no one should believe that there's a so-called premium signal...
There is no problem to use free signals in your trading. The main purpose of such free signals is to demonstrate their accuracy so that in the future such tragers will be transferred to a paid group. But no one will forcibly transfer you to a paid group of signals, demanding a fee for this, and you can refuse to use these signals at any time.