A totipotent cell with a full set of non-defective DNA, that is dividing, can and will become a full fledged organism if put in the right environment (think uterus). This is why you can split an embryo in two and get two babies. Eggs have been a convenient environment in which to let nature do the work of de-programming the DNA of a differentiated cell nucleus, so that the DNA in that nucleus will acquire the ability to develop into a full organism (e.g. Dolly, the famous sheep). When the DNA has already been de-programmed back into a totipotent state, the egg is not needed.
And I don’t know why you think that a truly totipotent stem cell can’t differentiate into germ cells. Where do you think germ cells come from? The science of artificial gamete production, starting with adult somatic cells, is actually pretty far along already.
I don’t think these are totipotent cells, as truly totipotent cells can only be derived from an embryo. These are stem cells that are deprogrammed to behave like totipotent cells. I am not sure of the technicalities, and am limited in my knowledge of genetics.
I am fairly sure that eggs are more than a convenient environment, they
are a necessary and essential part of reproduction. Without them, there can be no embryo, no fetus, and no unborn child. I think the entire point of this process is that the cells can be deprogrammed to act like the potentially beneficial embryonic stem cells, not that they have become or can become embryonic stem cells.