It is your prerogative to join these groups or not. You can always peek whatever they are doing and they may indeed give you good tips. But if they start shilling a particular never-heard coin, better get out because they are not here to help would be traders, but you will be rekt by their choices. You can always give them the benefit of the doubt and see what they are offering in their channel. If it is free, check what's in it, but if it is paid, better think many times before you spend that money.
That’s usually the aim of the majority of groups like this, they just try to gather as much people as they can and after they have succeeded in gathering them, which is definitely going to be noobs, they will start to promote some strange coins to them and trying to make them invest in all those coins and at the end, these coins never benefit them at all.
Anyone who is considering these groups should have a second thought about it. With that said, if anyone still decides to go ahead and join them, then they should be sure of what they are going into, never to rush and pay money when they are not yet sure.