The type aliases are extermely useful in C# too in the case the fully (or partially) qualified type name has to be used to to resolve the type specification.
If there are more than one element of the qualified name has to be specified then the replacement of the aliased types dramatically reduces the readablity of the code.

Example:

using MyEnum = MyNamespaceOne.MyNamespaceTwo.MyAnotherType.MyNestedType.MyEnum;
namespace MyNamespaceOne.MyNamespaceTwo
{
class MyType
{
class MyNestedType
{
void Foo()
{
MyEnum a = MyEnum.Member;
}
}
}
}

Would be replaced with:

namespace MyNamespaceOne.MyNamespaceTwo
{
class MyType
{
class MyNestedType
{
private enum MyEnum { ... };
void Foo()
{
MyAnotherType.MyNestedType.MyEnum a = MyAnotherType.MyNestedType.MyEnum.Member;
}
}
}
}

The workaround is to use the different name for the alias and uncheck "Do not remove using alias directives if alias name differs from teh imported type name" in ReSharper > Options > C# > Namespaces Imports :

using ImportedEnum = MyNamespaceOne.MyNamespaceTwo.MyAnotherType.MyNestedType.MyEnum;
namespace MyNamespaceOne.MyNamespaceTwo
{
class MyType
{
class MyNestedType
{
void Foo()
{
ImportedEnum a = ImportedEnum.Member;
}
}
}
}

Although the latter won't be changed by refactoring but it reduces the readablity of the code too - so I voted for that ReSharper feature.