Digital currencies present a unique issue of access. The same reason they are being valued, their security, is the same reason they present a unique issue. If you have purchased digital currency then you are aware there is more than one type of wallet you can use and more than one market or trading platform to purchase or sell your digital currency. There is a danger with digital currency, that without providing your agent some kind of breadcrumb trail it could disappear into the wind.
Now, imagine you know that a loved one had digital currency but you don't know what kind or where their currency is being held. If they can't track down where your digital currency is it will be lost. If you have chosen to use a trading platform that is based in the United States, like Coinbase, you can follow a process similar to that of regular bank accounts to recover digital currency. However, if the trading platform is not based in the United States there is no guarantee that they will have a recovery process like Coinbase. Part of the issue with digital currency is that currently digital currency is not treated as money under the law. At the very least, write down what kind of wallet you have (cold vs. soft) and which trading platform you have used to store, trade or sell your digital currency. That way your executor/trustee can find all of your digital assets (including the currencies).