They are equivalent. The only reason you find it problematic that a sequence of bytes is "invalid" (read: can't be decoded in your preferred encoding) is because you've manufactured the problem.
In the end, the only layer at which it really matters whether your byte sequence can be decoded is the font renderer, and just being valid utf-8 isn't good enough for it either.
In the end, the only layer at which it really matters whether your byte sequence can be decoded is the font renderer, and just being valid utf-8 isn't good enough for it either.