The spell example with the car is not a spell that tries to deal damage by hitting you with a car (i.e. using a scene aspect). That would result in a weapon 10 spell instead, as per the example grasping branches spell in the books (that one uses a tree for the extra oomph). The car spell simply does an 8-shift telekinesis acting on the car to move the car (on you). The immediate result of the spell is that the car lands on you. The secondary, and perfectly natural, effect is that you have a car crushing you with its weight; that deals damage due to the car, not the spell itself, and you have to be strong enough to push the car aside to get out of it.
Compare to using the same telekinesis rote in the following situations. The spell may do a very simple effect but depending on what you work with, it can have devastating secondary effects;
1) Throw someone off the roof of a multi-story building. The spell is a might 8 effect that throws the guy off the roof. He gets to roll any defenses he has against the spell to avoid being thrown off the roof and if he can fly or magically levitate he does not fall but if all those things fail, then he falls. And falling damage rules say 5 stress per 10 feet or so. Even if we cap that to 40 feet for max damage, a fall off a 4-story building is still 20 stress.
2) Break the bridge/floor under someone's feet. Doing the Gandalf thing is extremely effective in some situations. 8 shifts is a powerful enough spell to break through heavy exterior walls and similar things - small bridges and floors included. Not only does the enemy get to fall, but they usually get to fall into whatever the bridge was built over; an avenue full of speeding cars (that hit them), a river (which carries them away or might drown them), or a really, really deep ravine. In any case, they take lots and lots of damage and the encounter is pretty much over; they could survive but getting back at you would require a lot more effort than knocking them down did.
3) Break the roof. Just like breaking a wall, breaking the roof/ceiling not only does what the spell is supposed to do (break the ceiling with a might check) but the broken ceiling also gets to fall on whatever is standing under it. A typical ceiling for a 30x20 room weighs over 15 tons and even if you are hit only by a 2-ton piece, you still take significant damage and have to push the debris aside to escape.
4) Throw your target into high-votlage powerlines (or the powerlines into your target). This is a Holywood favorite and why not? If the fight is in the countryside near one of those 120k volt major powerlines or, even worse, in or near a power plant, use it to your advantage.
Long story short, a telekinesis rote is not very effective in combat if you have nothing to work with. But with the right declaration, assessment or existing scene aspect, it can be devastating. And it is also cooler than a pure damage effect because it encourages you to be creative and use the declaration/assessment rules and/or aspects beyond the point-and-blast rules. Besides, it is also useful out of combat. It can open paths and doors locked to you (by breaking the doors/walls), discourage pursuit (by flipping enemy cars), block the paths of enemies (by destroying the path itself) and it can even be used socially; never underestimate the persuasiveness of showing you can lift a car with your mind.
