Fixed-size characters can be helpful, but even if there is a fixed byte count per code point (as in UTF-32), there is not a fixed byte count per displayed character due to combining characters. Considering these incompatibilities and other quirks among different encoding schemes, handling unicode data with the same (or compatible) protocol throughout and across the interfaces (e.g. using an API/library, handling unicode characters in client/server model, etc.) can in general simplify the whole pipeline while eliminating a potential source of bugs at the same time.