This pops up every so often, and is wrong on several fronts (UNIX is UTF-8, UTF-8/32 lexicographically sort, etc.) There's not really a good reason to support UTF-8 over UTF-16; you can quibble over byte order (just pick one) and you can try and make an argument about everything being markup (it's not), but the fact is that UTF-16 is a more efficient encoding for the languages a plurality of people use natively. But…
From that perspective, keeping the data in UTF-8 for most of its lifetime also when loaded into a program, and only convert "at the last minute" when talking to underlying operating system APIs makes a lot of sense, except for some very specific application types which do heavy text processing.