I suspect you'll see more developers going the static jetway route because of AES, too much work to animate them.
Also because it's an easy way to raise fps, without worrying too much about optimizing the rest of the scenery. From slower to faster, it works like this:
- A scenery with animated standard FSX jetways (SLOWER)
- A scenery with static jetways, disconnected from the terminals, so it can be AES-able
- A scenery with static jetways embedded in the terminals, so it can't support AES (FASTER)
Of course, this is a comparison with all things being equal.
We always used animated standard FSX jetways, and our sceneries never were slower than anyone else (especially considering their usual size), and there are sceneries out there with static embedded jetways which are slower than ours so, doing FSX animated jetways on top of requiring more work to do them, will require more careful optimization for the REST of the scenery, in order to recover the performance loss due to the standard FSX jetways animation.