There are some platforms that provide std::optional but not value()! macOS 10.13 is one of them. You're forced to use the unsafe * operator on that platform. I

There are some platforms that provide std::optional but not value()! macOS 10.13 is one of them. You're forced to use the unsafe * operator on that platform. I cannot imagine the rationale that went into shipping std::optional support without value(), but they did it.