Time and time again it's been shown that if you design systems that are hard to correctly secure or make significant compromises in the name of "security", they end up being insecure because people just won't use them or will actively seek ways around them.
You can't just handwave away issues like usability and pretend that you've designed the "perfect" system or something.
If you design a good/secure keypad lock but it doesn't give people an easy way to let their family member in the house when they are away, they are just going to give out the code, leading to less security overall. If you design a secure keypad lock without a tumbler, the first time the batteries die and the user is locked out of their house they are going to replace it with something that won't lock them out.
Usability needs to be a core aspect of secure engineering. And oftentimes a "technically less secure" option is better, because it's actually usable by normal people in most cases.
A 5-point harness is safer than your average seatbelt, but we don't use them because forcing every car to have a 5-point harness would just end up with fewer people using them.