[zajio1am]

> C-h isn't some crazy invention of readline (...) that you got used to: it is the standard key code for backspace.

> C-H is equivalent to pressing Backspace!! Now, there is also a DEL, for the Delete key, which is which is 127

Not anymore on Linux terminals. People wanted to distinguish backspace and C-h, so in some time in 1990s there was great DEL-BS shift, where convention changed to use 127 for BS and some escape sequence for DEL (in direction from terminal to program, in the opposite direction the original convention is still used). That is why there are these sections in Emacs manual (and similar options on other tools) - to handle situations where terminal behavior and information about terminal are mismatched.