The most interesting part is that Iconomi keeps growing its funds due to the BTC rise and next week when LSK pumps it will go even higher. Fun times ahead on all fronts here

It would be interesting if they promised to pay dividends in USD.
Otherwise it all depends on BTC/ETH price, and the prices of other cryptos they (will) own.
No it doesn't. You can convert your ETH dividends to any currency, crypto or fiat immediately.
I don't see any problem here.
Yes, I can do it, but Iconomi must buy ETH to pay dividends.
If they have 1 BTC now and ETH is for 0.012 then they can buy 83.33(3) ETH, but if ETH will be 0.013 in a month then with the same 1 BTC they will have 76,92 ETH.
If that 1 BTC worth of ETH was used to pay dividends then with lower ETH prices ICN holders would receive more ETH.
Well, it depends person to person. Some person may prefer to keep the dividends in Ethereum, some may like to convert it immediately to Bitcoin or Fiat.
Also, they won't make profits just in Bitcoin. They would be making profits in Ethereum, Bitcoin, and other alt coins. Investing in ico would give them alt coins which would be converted to Ethereum directly.
And my friend, in world of crypto currencies such things are common. Many alt coins are very volatile. Bitcoin too is volatile.
It could also happen the reverse way. Eth btc rate could also go down .
It you don't want to take such risks convert crypto to fiat immediately.
If they would pay in USD, they would also invite Many legal restrictions.