It has no effect on the lifetime of the object, but it can affect the lifetime of the allocation. The reason is that weak_ptr needs the control block, which make_shared bundles into the same allocation as the object for optimization reasons.

Quoting cppreference [0]:

    If any std::weak_ptr references the control block created by std::make_shared after the lifetime of all shared owners ended, the memory occupied by T persists until all weak owners get destroyed as well, which may be undesirable if sizeof(T) is large.