My guess is that big whales don't bother to buy on each two exchange platforms as many XDN as they can, for a question of time. Better to have them all in a place.
Even at 156 satoshis XDN is still very cheap for a big whales. It's not as expensive as BTC.
I think that there are a couple benefits beyond pricing, too:
1) Redistribution of XDN to a broader audience. Basically it will allow others to have a larger stake in the currency without having been an early adopter etc.
2) Large investors can buy a bigger parcel of XDN at a time without heavily effecting the market price on the exchanges.
I think that the reason why people would buy the coins at 2-3x their current market price is because that could soon be the market price. When the XDN ICCO begins the selling phase, the price of XDN will probably catch up to the ICCO parcel price (per XDN) naturally.
I personally don't think the ICCO is a
necessity, but I do think it is a great
option. Meaning that I think it only opens more doors but is not a requirement for the coin's success. Holders can also choose to participate or not, but it is not a requirement. The tech is very strong, the community is growing, and the devs are on point. I think that the coin is extremely undervalued and that the ICCO price is still a great deal, especially when you consider it as a competitor to Monero (which it is--they were both forked from Bytecoin). It's interesting to look at the market caps and total coin supplies of Monero and Bytecoin vs DigitalNote. If you understand the crypto market and how those coins are perceived, you will understand why the potential with DigitalNote is huge.