These short term obligations burden them, alter their financial statements for the worse and sometimes put their very viability at risk. From the macro-economic point of view, it is always better to have longer debt maturities with less to pay every year. If firms and individuals do not take credits from the outside because they fear a devaluation - they help to create a monopoly of the local banks. It would be easy to conclude, therefore, that it is an important interest of a country to be open to foreign financial markets and to provide its firms and citizens with access to sources of foreign credits. If people fear devaluation - a responsible government can never promise not to devalue its currency.
Devaluation is a very important policy tool.
In many countries of the West, one can buy and sell insurance contracts called forwards. They promise the buyer a given rate of exchange in a given date. But many countries do not have access to these highly sophisticated markets. Not all the currencies can be insured in these markets. So, it cannot be insured using these contracts.