Thank you for your attention, I really appreciate your help.
As correctly pointed out VAR is a tool used in portfolio management and this is the area where I saw it applied (mainly equities). Nonetheless I see some validity in applying it for the risk management of currency positions.
Let's say that as a trader I have a daily loss limit of 5000 and the VAR 5% over 1 day of a lot of EURUSD is 3000 (just guessing), therefore I could be led to consider positions of 1-2 lots instead of 10 lots if I want to avoid using stop losses.
Of course for this kind of sizing it could be more useful to consider the distance of resistances or supports, VAR would be only a complementary check.
But please consider taking concurrently a long position in EURUSD and a short position in AUDUSD. Given the (generally negative) correlation, the total VAR is not equal to the sum of the VARs or the single position but lower. With even more complex situations VAR could become very useful to evaluate exposure provided you use it with other risk management tools (especially in the tails)
I have never applied VAR in thsi environment but I would like play a bit with this idea to see if it can help