I used to make a soup every time my parents came over because they loved it that used a lot of chicken stock. Eventually I gave them the recipe and they'd make it at home with bouillon cubes and then call me and ask me why it wasn't as good. To this day they still haven't tried just making their own stock, but I did eventually get them to try the liquid stuff that comes from the store, which is a tad too salty usually but still much better than cubes.
Fresh stock is a necessity when it's the main part of the dish; cubes are fine when they're used for adding just a little bit of flavor. Convenience matters.
Also, you can make excellent stock from (raw) chicken wings, that cost next to nothing (you don't have to save bones from roast chicken -- although roast chicken is one of the most delicious foods there is).
It's also good practice to always buy unsalted or low salt stock (same with butter!) so you can control the salt intake yourself. And you'll look healthier at the check out!
The scientific consensus on salt seems to be changing. I think that current thinking is that salt is unlikely to be a major influence on health, all other factors being equal.
There's a lot of evidence that ordinary healthy humans need a particular amount of salt each day (adjusted for activity, age, etc), with not much variation. There's some epidemiological studies that show that most humans do end up consuming that amount of salt - i.e. the physiological->psychological feedback loop that triggers the impulse to eat salty things is well-controlled.
Eating both too little and too much salt can lead to very major health problems.
Popular fads on salt in diet changes all the time though; luckily that can't stop our bodies (unlike problems with anorexics; junk food; sugars; etc)
Regardless of health effects, cooking with unsalted varieties (stock, butter, etc) allows you to control the amount of salt in your dish. You may end up with an over-salted meal if you use salted butter, etc.
I used to make a soup every time my parents came over because they loved it that used a lot of chicken stock. Eventually I gave them the recipe and they'd make it at home with bouillon cubes and then call me and ask me why it wasn't as good. To this day they still haven't tried just making their own stock, but I did eventually get them to try the liquid stuff that comes from the store, which is a tad too salty usually but still much better than cubes.