Water-based ganaches are nothing new - I have personally known about them (and have made them) for at least six or seven years. I have also known people who have been making them for a lot longer (it's where I learned about them). So Damian Allsop is not at the vanguard of anything - he's just doing a good job of PR in a market that is unaware of the history of this area.
Cream has a flavor, and while fats do a good job of transporting flavor, the flavor of the cream (and other dairy) will mask other flavorings in the ganache. The fat in the dairy helps with emulsification, so it requires more work to create a stable emulsion with just water. Immersion blenders are just the trick here - doing it by hand is not the way to go.
One thing the article got wrong was the idea of a chocolate and water shell. There is no reason to do this and, technically, it won't work. Another thing the article confuses is conflating ganaches with mousses. There's no reason to add egg to a ganache. Most knowledgeable people will know that, but people with less experience might try to figure out how to add eggs to a ganache.
Another thing to consider is the solvent used to extract flavoring.
Take a cinnamon stick, for example. You'll get different flavor components with water, oil, and alcohol extractions that can deliver a far more expressive version of cinnamon than any one (and water is the one on the tongue). If I were working on a new cinnamon-scented water-based ganache I would look to blend my own extract of cinnamon from a variety of solvents. This technique can be applied to any number of herbs and spices.
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@DiscoverChoc