thank you for all of your opinions
it really helped me in making a decision

what would you do if a newbie said he could develop your money and he asked you to invest money in him ?

financial pyramid is a financial scheme that has no utility value
for me bitcoin is very useful to save budget when we want to transfer some value of money abroad without a third party
so, for me bitcoin is not a financial pyramid
and the answer to your question is: Myth.