Why not, why not predict the future!
It's impossible to predict the future, lol..

But, a well trained NN is not created to predict the future, i think all you are looking at the NN with a wrong attitude, a NN should be like a intelligence, like humans have, look at it as a entity, that can think, can calculate, and can choose.

Now, you get a NN, and train it, let it (he?) study the forex market (studying the chart), and let it study and study, when a certain time the NN say: well i understood everything, try me and i let you see that i've understand how price work (you query he by letting it doing some backtest).

Then ask to him (or to yourself): if you understand and understond how price work (worked in the past), surely you must have built a strategy, an algorithm, some thinking method that let you out of bad trades in these 5 years (5 years of backtest for example), now.. apply this strategy/algorithm with the future price, if you really got the perfect strategy (that worked well in the past 5 years), there are good probabilities that it will continue to work well for the next year!

And, it may work, for the next year, or for the next 10 years, or only for the next 5 days, i've worked with NN for some years, and i know that it can work, but at a certain time it just stop to work..
But i noticed that if a NN is trained well, and with a big amount of data, the results it give out are more (much more) then 50% right, neural network can work great! The only problem is how to integrate it with MT4, because i found that it is impossible to create a good NN with just mq4 code, and also to well train a good NN it is needed a too much powerful computer (compared to what i use), but it work.

Just my opinion

__________________