This is a common misconception about UTF-8 vs. UTF-16. You're missing two important facts.

1. Most UTF-8 string operations can operate on a byte at a time. You just have realize that functions like strlen will be telling you byte length instead of character length, and this usually doesn't even matter. (It's still important to know.)

2. UTF-16 is still a variable-width encoding. It was originally intended to be fixed-width, but then the Unicode character set grew too large to be represented in 16 bits.