It actually depends. A weak currency doesn't necessarily mean the country won't anymore engage in global trades. As a matter of fact, a weak currency could actually be designed on purpose. It could actually be intended by way of a policy to be used as a strategy in order to increase trades, exports in particular. In which case, since the currency is weak, exports are cheaper, making them more attractive for buyers compared to their competitors. Of course, there's also a need to balance since a weak currency would also mean imports are expensive.