What's the archetype use for Rc anyway? I don't see the point in having a reference-counted object with single thread ownership. Also you only pay to synchroni

What's the archetype use for Rc anyway? I don't see the point in having a reference-counted object with single thread ownership. Also you only pay to synchronise shared_ptr when you take a copy of the pointer... I can't think of anywhere in a sane, well-structured algorithm where this would bite.