If they are gapped out on transmission capacity, then they can produce it but can't send it to India, in which case doing something locally with it woukd be useful.
Per a Bhutanese source, it has been mining BTC since it was 5000$. Also, the electricity is free so it hasn't lost any serious money given the low expenditure. Last time BTC was 5000 was in Mar 2020 so given that they are still doing it, I don't see why this is unprofitable for them. If it was, they would have stopped by now.