Thank you. But this would require to end or seriously limit the abbility to use fractionnal reserve. And how would bitcoin do that ? As long as there are major financial institutions with enough trust from people, I see no limit in loans. (Micro)Strategy could one day lend 100x their bitcoin reserve in any new bitcoin-backed coin. Or I am missing something ?

Bitcoin will end fractional reserve banking. Bitcoin will replace the fiat banking system. What you need to do is research and read up on what is sound money and how sound money works. You need to understand how the old system works in order to understand how Bitcoin works.