This precisely proves my point. I would say though that it's not efficient at all. Multi-level marketing schemes are only loss of time and, in many cases, loss of money as well. That is for 90+% of total amount of participants. To reach the top of the ladder is very difficult, if not impossible. And, while those from the top of the ladder live nicely on the efforts made by the ones below them, the other ones are sweating and working hard for finding other referrals or for completing various tasks assigned to their level.
What I said above is speaking at large about pyramidal schemes. In some cases, these schemes are Ponzi schemes, such as One Coin or Bit Connect and, in these cases, situation becomes even worst for participants.
My advice? Stay away from any MLM or referral scheme. You'd only save your time, neurons and money.