It is very important for a person interested in currency transactions to realize a significant difference between “speculation” and “investment”. Inherently, exchange trading is a speculative activity. Foreign exchange markets are the most unstable markets in the world. When trading is held with a usage of margin, the trading cannot become stable.
A diurnal exchange trading can be extremely profitable. Heavily risking market participants can earn an overwhelming percent of their incomes per single day. But from intellectual and psychological view points, a diurnal trading is a very hard job. Generally, a diurnal trading is a speculation and it is a general activity of diurnal traders. However many people engaged with exchange deals are not professional diurnal traders.
People using services of exchange brokers often engaged in different fields of activities. This people just opening one or another position and do not participate in diurnal trading. This is also a speculation and it shouldn’t be mixed up with investment.
As a conclusion, inherently the exchange trading is not so much connected with investment as with speculation and hedging (hedging is used only while working with forward instruments). In some ways it is possible to invest into currency with a long-term outlook; but to perform such a deal, it would require a large amount on your account and low ratio of borrowed current assets to your own.