So I didn't say that you shouldn't have any salt in your seasoning, but that most seasonings - especially most montreal steak spice blends - have way, way more than they should, and that caking salt on a steak is not a good method. To respond to your points individually,
1) If the flavour you're going for is "salt lick", sure. If you like your steak really salty, fine, go nuts. I'd rather have other seasonings that bring out the flavour of the meat.
2) As you say, minor, and you shouldn't really need the help on that one.
3) This is true, but again, not necessary if you're searing properly.
4)
You want a
crust of salt on the steak? I mean, leaving aside the fact that any number of seasonings create "mouth feel" just as well (
the one I suggested is here, and contains things like mustard seed and chiles that have their own texture).
It seems to me that people who liberally apply high volumes of salt to steaks are only comparing the result favourably to a bad steak cooked badly. I can certainly see it helping quite a bit if your usual cooking method is otherwise producing dry, bland meat, but if you're doing things properly you don't need it to get good results and you can spare yourself an excessively salty steak.
Either that or you just
really like salt, which, well, personal preferences I suppose.