I've never been in a paid trading group. But I heard that there are a lot of groups that give a good signal at the start and disappear in the end. That's what made me confident to study on my own and I think I've made it this far. Besides that, actually there are also several trade groups with free signals or just a discussion that I participated in. I only take advantage of the moment from the group if according to the results of the analysis it is appropriate then I will enter if I don't let it go. This means we have to be good at filtering and taking advantage of the moment.
I have been in some and you have missed nothing by not being in one at all. I can tell you that most of them are either fake, or they are giving information that anyone can find anywhere, even youtubers share that daily as well if you follow some trader youtubers, I have seen even stramers who make moves that you can watch for free as well, so all in all nothing special goes around in those groups.
Most of them is like "oh macd is this, so you should sell" or "oh weekly is this so you should buy" and so forth, which never really means that bitcoin will do what they claim it will do, sure it "may" do that, but that doesn't mean that it worths money, I think what they do is not something that worths paying for. I think they should do streaming and if they are right, they would be making the moves themselves, and if they are wrong they lose money as well, at least brings some credibility to it.