Kosher salt vs. Table salt for rib eye steak
The reason people choose Kosher/Sea/Rock salt over table salt is mainly down to the crystal size and the lack of additives like iodine.

Kosher salt is less soluble and less dense than table salt.

The large crystals in these salts mean that unless there is a fair bit of water present they don't completely dissolve. This means it is less likely you'll over salt steak even if it's caked in crystals.

Table salt will dissolve with far less water present and will, therefore, get absorbed more easily into the meat. 

Also the lower density means you can liberality sprinkle Kosher/Sea/Rock salt on things and even if it does all dissolve you've actualy added less salt than you would think. It looks like a lot but 1g of Kosher/Sea/Rock salt takes up a lot more space than 1g of table salt.

1tsp table salt would be way too much. I'd go for about half the volume of Kosher salt if you were dissolving it in liquid and maybe as little as quarter the volume if I was using it as a rub (as in salting a steak).