Defaults matter is an instance of Lowering the friction may exponentially influence the usage when one alternative is easier to use than another one.
In C, to create an immutable variable, you need to add
constto its type (creating mutable variables is one word easier), so this leads to more variables created mutable (even if they are not mutated). It takes discipline to create immutable variables. For contrast, Rust uses
letfor immutable variables and
let mutfor mutable variables. This leads to a significant portion of variables created as immutable.