Truth be told if bd was in this situation srilanka would have been the last country to help us. The fact that our govt. is willing to accept the payment in worthless srilankan rupees speaks volumes
It is not just altruistic.
Yes BD does get Sri Lanka Rupees in return but this will be with interest.
The sums are not that great and it would be easy for BD to quickly(1-2 years) buy Sri Lankan products to this value and so in effect this is win-win for both countries. Last year BD brought 160 million US dollars of Sri Lankan products.
When you have near 50 billion US dollar reserves then 200 million US dollars is not that big a deal.