Dual citizenship, frankly, doesn't make much sense for Nepal (in reference to Nepalis in US), but if granted, I might consider it.

Instead of looking at why one would need it, let's look at the circumstances after one gets the dual citizenship.

The person would want to live in Nepal or US (remember we are talking about Nepalis in US only). Say the person would like to live US, then why would Nepal grant citizenship to this person? Just go with NRI model, if you don't even care to live in your country then you don't deserve a citizenship. As for the properties that belong to you in Nepal, we should have provisions for NRNs without having to invoke citizenship issues.

Now, say, you want to return back to Nepal but retain US citizenship. Understand that as a US citizen, you are liable to pay income tax to US regardless of where you reside. Does having a passport make sense while having to pay dual taxes every year (US grants foreign tax credit but you still have to pay the differential)? To me it doesn't.

I'd do it if I were coming to Nepal for retirement and don't expect income in Nepal.

Again, I still cannot fathom the idea of one person being a citizen of more than one country - but I am not going to argue either.