Every single time I reload the page the other characters are a broken rectangle, so experimentally it's 100% of the time I'll need that character. What I want is to not see a broken rectangle. One can't say that U+76F4 is useless when it clearly is serving a use for my computer.
OP means it's the only one that renders at all. It could be wrong but the other two are just missing-glyph boxes which are definitely wrong. Those code points appear unusable as a practical matter.
You don't want U+76F4, you want buggy Asian fonts to be fixed.
(On second thought... did it render correctly for you? Did you check?)