To an ignorant person, the greenhouse effect isn't simple. Not because the idea itself is complex, but because it implies we can and should do something about it.
And ignorant people would rather tell themselves it's not man-made because that would mean we can't fix it and, therefore, don't have to.
See Ian Danskin (if you haven't): https://youtu.be/dF98ii6r_gU
Edge has a feature that lets you install websites as PWAs, which appear in the Start Menu like any other app. I assume they plan to have people use Word Online that way.
Whether or not this will be set up automatically is a different (and more important) question. But if they don't do it automatically, it's something that would only need to be done once.