Im gonna ignore the fact that moving state to other place completwly misses article point, but:

Two Users create exactly the same resource with the same tags.

Which one should be removed by Terraform?

Now either way lets ignore that.

You want to refresh infrastructure to know what to do. Without the state you have to go through EVERY API CALL on every service even those you did not create to be able to determine the whole state of the infrastructure which would be super super long action.

Without dependencies you would also have to maintain and build dependency tree EVERY TIME you would try to apply infra.