So, is BTC really the ideal tool to replace banks in typical loans and mortgages, or is it only designed for big players and small-scale charity "loans" like we usually see in this forum?
No, on the contrary. What is going to be set up, and has already begun is an entire financial services industry around bitcoin in which you can contribute your bitcoin as collateral to obtain loans (but remember ‘not your keys, not your coins’), just as products such as securities have been created, such as those launched by Strategy, which are a kind of corporate debt to capture market share in financial markets currently occupied by bonds or dividend-paying stocks. So it's all much more complex than you're thinking.