Mark,
On the tee of most par 4s (and 5s) the player has to consider where he wants his tee shot to end, to set up his approach. On good holes that gives a choice of distance and direction, in the knowledge that the shot to be executed is intended to give the player the best option for a full second shot.
Perhaps I'm just wired differently, but I see this situation taking place on a par three as well.
You walk on the tee and have to, with consideration to your own ability/form, work out the best place you can reliably (taking into account a relative approach to risk and reward) hit the ball to simplify the second shot.
Just as it is preferable to have an iron shot to a pin you can easily approach from a good angle over one that must carry a bunker, it may be preferable to have an uphill chip from short grass over a bunker shot or even a putt of a similar length that has to travel down a swale.
The decisions may not be as great in magnitude on a par three, but every golfer is still making the same decisions on a short hole as on a long hole.
I don't think you can say as a blanket statement that placing your ball off the tee on a longer hole is more or less important than placing your ball on a shot into the green. It depends on the hole and the golfer.
It's true that distance off the tee on a par three is a more focused issue than off the tee on a longer hole, but with smaller tolerances between good and bad in a lot of cases, I can't say I agree that it's less important.
On the 3rd hole at Sandwich, staying below the hole is one of the most important things you can do on the whole course. On the 7th at Barnbougle Dunes, you're often choosing the best miss on a 100-yard hole. Missing left there is one of the cardinal sins in golf - far greater than being on the wrong side of a fairway elsewhere on the course.
Re: this comment of yours:
The player may not choose the distance to the hole but, if he doesn't it will be because there is a place on (or, just possibly around) the green which is a far easier or safer target and gives a good chance of par or birdie. The player is not setting up another full shot and the considerations are completely different.
Why are the considerations
completely different? Isn't the common thread a desire to place the ball in as ideal a position for the subsequent shot as your ability will allow?