Probably the same reason they use the word “model” instead of just calling it an embryo. They don’t want to make it sound like they’re experimenting on an actual human embryo (even though that’s basically what it is). That’s the real ethical question here. At what point does this become experimentation on humans? This also steps into basically the same problem as the abortion debate, which is more heated than I’d like to get here.
Probably the same reason they use the word “model” instead of just calling it an embryo. They don’t want to make it sound like they’re experimenting on an actual human embryo (even though that’s basically what it is). That’s the real ethical question here. At what point does this become experimentation on humans? This also steps into basically the same problem as the abortion debate, which is more heated than I’d like to get here.