Why do so many dessert/biscuit recipes have salt in them? Whilst I can understand salt in the majority of recipes, I never really understood why it is in so many desserts or biscuits.

When I have asked a few friends or family who do a lot of cookery, the vast majority say pretty much the same thing "the salt cuts across the other flavours", or "you always just add it!".

But... So many times, when I eat biscuits, if I chew a lot and then just as I swallow, I can always taste salt... The ones I probably taste salt the most on are (Worst first) : Custard Creams, Digestives, Rich Tea.

In my honest opinion, the salt just isn't needed - I don't think it adds anything, and, it just seems to leave a horrible after taste (I can usually always taste it, but a lot more when I chew a lot).

In particular, now that so many people are on low salt diets and so many people say it is bad for you, I don't understand why it is there!

So, is there a good reason why it is added?
Salt has unique properties in how it interacts with the taste buds. While it has its own "flavor" it also has the ability to enhance some flavors while blocking your ability to experience others.

While I could go on, all I would be doing is repeating much of what I learned watching 
The Food Network's Alton Brown. He goes in depth for the episode "The Ballad of Salty and Sweet" which is available on from the Food Network.

There are (of course) other resources, but AB does a really great job of teaching in this episode.