People get too crazy with the advantage of a double boiler.
Depends what you mean by crazy... It is a fact that you cant independently vary the steam power and temperature on an HX machine. They are coupled - it is intrinsic to the design. There is
zero doubt (in my experience) that HX is a very, very clever and functional compromise. I make great coffee every day in my almost 20-year old HX Giotto.
I have had extensive experience on multiple HX machines, one double boiler E61 and a substantial two-group Nuova Simonelli Aurelia (I think that was the one)... You can make drinkable coffees in all of them. But they offer difference work flows and capabilities. Dual boilers don't necessarily make a better drink but they are better at keeping up with demand. From a purist's point of view... dual boilers are also more temperature stable. They aught to be capable of producing a higher load of consistent coffees.
Australian coffee drinkers are biased towards milk drinks (at any time of day). If you have a group of friends over... you'll be wanting to make lots of flat whites or cappuccinos. You can either do that fast... or you can do that slow!
If you are I to milk drinks, you really can't tastes the subtle notes of coffee.
Milk changes the flavour profile and mouth feel. It is another parameter where you like what you like and there is no right or wrong. While I agree that milk can swamp the subtitles of beans... it doesn't
have to eliminate all of them. It all depends on the bean and milk combination.
I like a medium bean and enjoy nutty/caramel/chocolate/salty flavours with milk. I agree that I haven't really experienced the fruitiness of a lighter roast in a milk drink... but then again... I dont like bright/tart/acid with milk either!