[devinus]

That might be a valid criticism against e.g. Bitcoin with a 30 minute confirmation time, but if you send your friend $10 worth of Nano they'll have $10 worth of Nano by the time they receive it, ignoring whatever they decide do with it.

[atomical]

That's assuming that they can immediately send it to an exchange. Maybe my friend is sleeping or at work. In the time it takes for him to proceed with the steps of transferring to an exchange and cashing out the price in USD may have gone down.