The difference would be the phrasing and specifics. "Magically switch trans people to the assigned sex at birth that they desire to be?" Works for some. "Magically make trans people's bodies align with their specific and nuanced gender identity" is less of an issue. The problem you run into with the first is some are not interested in surgeries or are non binary so a full surprise sex swap would not be what some trans people want.

I still think consent is important though, even if the way the magic works is basically "they get what they want". As much as it is hard to imagine, there are also trans people who do not want to transition at all due to having family or friends who would cut them off (I think that's a pretty awful and tragic situation to be in, but imagine the trans woman who magically changes to the shock and anger of her deeply religious family or SO, who then ostracize or reject her, or even react violently). You aren't likely to be murdered for recovering from cancer, but in some places magically shifting assigned sex might come with some pretty awful, bigoted strings attached