Because by definition binary means only two characters can be used.
But yes there is a trinary system in which you can use 3 characters. And 4, and basically any number.
Whether they are used or not depends on how useful they are. Binary, octal, decimal, hexadecimal are examples of them.
What’s the usefulness of binary? That it’s the simplest in terms of how many symbols it requires: only two.
damNSon189 t1_j9v7yya wrote
Reply to ELI5: Why do we only use 1 and 0 for binary? Could we create a trinary system introducing an extra '2'? by No-Mammoth-1638
Because by definition binary means only two characters can be used. But yes there is a trinary system in which you can use 3 characters. And 4, and basically any number. Whether they are used or not depends on how useful they are. Binary, octal, decimal, hexadecimal are examples of them. What’s the usefulness of binary? That it’s the simplest in terms of how many symbols it requires: only two.