Let me clarify something here, I use Baleine sea salt at home not at the restaurant. It takes me almost a year to go through one container at home. In the restaurant we buy our sea salt in bulk from Giusto's and it's downright cheap: 7.50 for a 50 pound bag--comes to .15 cents a pound. As I've said before, Tom Lehmann's thing is commercial pizza, not artisan pizza, so using sea salt for the average operator doesn't make sense. However if you are using special flour, fresh mozzarella and San Marzano tomatoes for your pizza, you should be using sea salt. On the commercial level, if an artisan pizzaiolo is making the ingredient commitment, why scrimp on sea salt when it is clearly an inexpensive yet key ingredient. It is doubtful that one might actually taste the difference in a dough, but it goes beyond that. If you are committed to using only the finest and purest ingredients for your pizza, sea salt is the way to go. If you want to consider yourself an artisan pizza maker, you wouldn't use anything else. Artisan pizza is not just about technique, it is equally about making pizza with the purest essential ingredients. Every component of artisan pizza must be looked with the same importance. If you are only going to use flour, water, yeast and salt (and occasionally olive oil) they must all be of the same quality.
As for the extra expense for the home cook, you can purchase sea salt in bulk at health food stores and it is much cheaper than in a container like La Baleine. I like La Baleine, and I especially like the handy container, but I use so little that it doesn't really cost me that much in the long run. I use the Giusto's bulk for baking at home though, because I only use the La Baleine as a finishing salt condiment.
Also in general cooking, you certainly can taste the difference. I don't like the way regular table salt tastes. Once you get used to the pure flavor of sea salt, it becomes impossible to go back.
PS: At my restaurant we use sea salt on the tables as well...