For quite some time, I maintained a .10% NaCl content in my planted tank. (That's 1000 ppm.) Many plants grew VERY well, such as jungle valis, madagascar lace, anacharis, and cabomba. Some plants altered their growth form. For example, the anacharis grew very thick stems.
Despite the above, I found that the tank did much better without any NaCl at all, and have not dosed any for years now.
Personally, I would not use it unless you are creating a planted tank with brackish water fish.
The question is why use salt when it is not necessary? I wouldn't if I were you. Not even in a planted tank. Note that some fish and plants will not tolerate salt for a long time.
Fish will do well regardless of whether or not you have salt in your tank. True that the salt prevents most diseases from infecting your fish but we also have to note that most fish are not tolerant of salt on long-term basis. Another thing, maintaining your tank and giving nutritious foods to the fish will strengthen the fish's immune system thus allowing them to fight off diseases without having too many problems at all. Medications are usually last resorts. Most fish can recover without any interference by aquarists.