But why would I want to do this instead of just having multiple lambdas that capture the same values by reference, or using shared_ptr and synchronization? I ca

But why would I want to do this instead of just having multiple lambdas that capture the same values by reference, or using shared_ptr and synchronization? I can see lifetimes of the data being an issue, but you shouldn't be calling std::visit in a way where that could cause a problem without synchronization anyway.