So talk me down -- if you're at a great natural vista, why wouldn't you use this lens?
If it's what you've got in your bag, sure, of course, use it. And it'll just just fine.
But if you're looking to get a 24mm lens to shoot landscapes, the TS-E 24 outperforms the 24 f/1.4 by such a significant margin at that sort of thing that you'd be silly to get the 24 f/1.4.
And, similarly, if you're looking to do environmental portraiture...well, yes, the TS-E 24 can do that as well as the 24 f/1.4 can do landscapes, but the 24 f/1.4 is so much better than the TS-E 24 at environmental portraiture that you'd again be silly to get the TS-E 24 for environmental portraiture.
I'd even go so far as to suggest that, if you do a lot of both, you should have both lenses....
It's like choosing between a minivan and a pickup truck. Can you haul a bunch of stuff in a minivan? Sure, but would you really want to? And can you ferry a bunch of people in a pickup truck? Again, yes, but why?
Horses for courses and all that....