Cells are no different than the stored programs concept that kicked off modern computing. They're machines that encode and run themselves. They manufacture useful resources: insulin, antibodies, heart tissue, etc. The same applies at the organismal level.
Once we get into regenerative cloning, we'll have an unlimited supply of blood for transfusions, organs for those needing transplants, and a research test bed that is orders of magnitude better than the methods we use today.
What I'm getting at is that we'll eventually create monoclonal brainless humans. Turn off brain development or surgically remove the brain during early development. Without a brain, these thoughtless bodies are not persons and are 100% ethical resources to use for the betterment of mankind. We'd be growing plant versions of higher level human tissues, and that unlocks so much new potential.
You'd probably birth them in chimeric pig uteruses until something wholly artificial is developed. You keep alive artificially through mechanical innervation and "life support". This requires a lot of research and development, but we're not that far off.
Different lines could be developed for studying certain cancers. When you can reproduce cancer and study it repeatedly at the organismal level, you can develop novel strategies for detection and clearance. We could make so much more progress.
The "transplant" lines would lack HLA markers that cause tissue rejection, making their tissues safe for transplant into anyone. Nobody would need to take life-altering immunosuppressants ever again.
We could probably start replacing thymuses and other tissues that deplete over time, potentially regenerating youth in humans and extending lifespan dramatically.
Biology is an evolved machine. We should start treating it as such. Then we'll truly be advanced.