Lossy is fine in some cases, but in many cases you do actually need the specific text you're trying to store - not just something similar to it. Hence my objection to "never any reason to use these characters literally".

> Your contrived example [...] if someone really wanted to store those two literal non-visible characters in a text file

Needing to store these specific characters is rare, but needing to store arbitrary text (possibly from adversarial/mischievous parties, or just a large enough dataset that encountering all edge-cases is inevitable) is common. For instance, for security reasons a log shouldn't break or have a blindspot for folders with those characters.

> as long as you’re ok with those characters not being valid data it works fine

Which is what I'm saying in my original comment with "or alternatively, a restriction for the stored text not to have them"