There are reasons to prefer virtual humans that are not "virtual humans are resource cheap". 

One of them is life expectancy. There is probably some limit to how reliable bio humans can be. 

Another is shear cool stuff. If you want magic that works like your favorite fiction, then that's often trivial in a virtual world. (Few exceptions around timetravel, logical contradictions etc) But something like a box that's bigger on the inside is much harder to make in the physical world. A wider possibility space allows more extreme optimization for fun. (Although that level of optimization is already pretty high with nanotech. And quite a lot higher in parts of todays world than anything in the environment of evolutionary adaptedness) 

Now this doesn't distinguish between uploaded minds and brains in vats. 

Another advantage of mind uploading is in enhanceability. Suppose we want to be able to fit 1000 years of memories into our minds. Not like right now, we have >900 years before we get to needing that for most people. But we will need that eventually. With digital minds, you have total freedom about how to do the enhancements in a minimally invasive way. With physical brains, you start getting physics problems.

Also, the amount of resources needed for a physical mind is not some fixed number. We (in a sense) use a bunch more resources today than our ancestors did. And have better lives because of it. There is a minimal level of resources needed to keep a person alive at all, and then a diminishing returns tradeoff curve where more resources = better quality of life. Virtual worlds mostly short circuit that, I think. I strongly suspect it should be possible to make nearly any virtual thing, to a quality sufficient to fool humans, with an amount of compute comparable to that needed to run the virtual human. Ie if you have a virtual human on a virtual beach, you can spend unlimited compute tracking every molecule in that ocean, but if it only needs to look close enough to the human, I doubt you need orders of magnitude more compute on it than you do on the human. (The human knows their world is virtual, but thinks pixelated waves are ugly) As opposed to a physical society, where regular rocket trips to mars could take millions of times the minimum energy needed to sustain a human.

There are a few exceptions to this, if some mathmatician wants to know if the rienmann hypothesis is true, they don't want an answer that can fool a human. A coin toss can give them that. They want the real answer. Which could take huge amounts of compute in a real or virtual world.

Other advantages of virtuallity include the ability to run different minds at different speeds, and the ability to copy people. 

This gives lots of reasons to go virtual, even if it is more expensive than the minimal subsistence human. 

If we succeed at AI safety, humans will probably decide the future of the universe

There are two levels of success: humanity gets to live, and humanity keeps control of the future. An AGI as aligned as a human has a decent chance of giving the currently alive humans either boon. A pseudokind [LW(p) · GW(p)] AGI that's not otherwise very aligned only allows humanity to live, but keeps the future.

(I have Yudkowskian doom levels for losing control of the future, assuming there is no decades-long pause to figure things out, but significantly less for everyone ending up dead.)

Personally I think that making the whole future a place I would want to live sounds like a good idea. 

Well given existing other human minds, some room for things that they would enjoy and that I wouldn't can be made. 

two scenarios [...] biological humans [...] digital humans, posthumans, computronium, hedonium, “paperclips”

It is possible that a specific version of the second scenario is "better" (whatever that means) than the first scenario. Getting this right is extremely important, as the entire universe literally depends on it.

Individual humans should have a say in shaping their share of the universe, especially their own mind.