The other point that Kant is trying to elucidate here is that reasoning in such a way depends upon a shaky prediction about future outcomes. There are thousands of ways we can go wrong in predicting what might happen.
His other point is that prudential reasoning depends on us knowing future events. Because not er'body is sweet baby jesus this is not going to be possible. The consequences of our actions are not discernible or if they are it is only in a very limited sense.
By the By, is it wrong to tell people that a blog entry with be the greatest thing they'll ever read and then it isn't? But what if it's to get them to learn philosophy?