Hmm. Is that so? Still, the book seems to say that magic requires the user to concentrate everytime they use magic and while they are using magic as said by many of the users, that includes Tom, Lenamare, Jehanna, etc. I actually thought that was the reason why Zargoffelstan escaped his warding. It was because Hortwell loss concentration.
We also seem to be comparing apples to oranges. Bookmaking, weaving and glass-making is very different from swords, shields, armor and gates. The first are crafts while the later are equipments. Unless you have the Disney type magic where a wave of the wand makes the scissors, needles, pins, etc. to come alive, fly around and start sewing a beautiful gown by themselves; then you are still be going to focus your mind through all the dreadful stuff of sewing the gown stitch by stitch.
So even if magic makes things easier for wizards than for ordinary people, it should not be to the point where books, paper and pens (and other items) are ‘nothing of real value’ to someone like Jenn.
As for the carpet, even if it just hovers in place you are still flying. You are just flying it in place. Also the car analogy is bad. For one thing, if the car isn’t moving, you cease to drive. A more appropriate analogy would be a helicopter. You can make the helicopter just hover in place, but, unlike the car, you are still driving it. It might not use as much mental energy to keep the helicopter hovering, but you won’t start playing candy crush.