Inconsistent behavior between json::get and static_cast intended?

[pasbi]

I have a custom adl_serializer for std::optional<T>.
I'm able to deserialize std::nullopt from nlohmann::json{} using get, but static_cast fails:

• nlohmann::json{}.get<std::optional<double>>() returns nullopt as expected
• static_cast<std::optional<double>>(nlohmann::json{}) throws.

Is this behavior intended?

https://godbolt.org/z/TEGqnTcoP

[nlohmann]

With #4036 we recently updated the conversion from/to std::optional. Please check with the latest develop branch.

[pasbi]

It's the same on the develop branch.
Actually, the question is more general.
I supposed that static_cast and get do the same eventually and was surprised that they behave differently.
This particular case serves more as a kind of demonstrator.

So let me rephrase my question:
Is it intended that static_cast and get behave differently in some situations?

[nlohmann]

get calls the explicit conversion via from_json. From the documentation:

The function is equivalent to executing

ValueType ret;
JSONSerializer<ValueType>::from_json(*this, ret);
return ret;