I will tell you my personal experience,
I started using telegram because of signals groups, I found them pretty useful. Then, one day I've told of pumps, those beautifull 200%, 500%, or even 1000% profits. I've joined one of those groups t.me/whalesinfo , which apparentely partners with other groups in order to generate a big market volume.
This is how it works:
Their admin buy the coin, then they post it in their channel the price goes extremely up, then it goes back to start price. Obviously you see what doesn't seem to work here, admins get to make a lot of profit. But even with that I gave it a try, first pump, +70%, second one, -60%, third one +130%.

To sum up, I hate the fact that the admin does not tell he buys the coin before, but even with that, I think its a good way for making quick high profits, as long as you keep in mind its also at high risk.
I will personally keep using their channel cause I'm making good money with it, but keep in mind this, the admin is making even more.