As stated in the article, the whole point is for use in ready-to-drink coffee manufacturing.
An average coffee shop's espresso machine might use $200/month of electricity, so even though the percent saving (75%) is high, it's off a base that's small relative to other costs; possibly too small to be enticing.
If you're drinking light, floral and acidic coffees, it's been relatively "trendy" recently to skim the crema off before drinking it.
I don't bother with that, but pulling two shots and removing the crema from one of them and trying them side by side is an interesting sensory experience — I'd encourage you to try, at least once!
Cold drip coffee is a thing, done well a very nice thing.
Technically you can also buy a bottle of grape juice from the grocery store, let it sit on the kitchen sink with a yeast lock for a few weeks and call it wine, and technically it even is, but it's also going to taste quite shitty.
You could just read the linked paper?
> Esp was prepared using a Sanremo Cube espresso machine. Brewing parameters were standardised following the supplier's guidelines: extraction time of 35 ± 3 s, pressure of 9 bar, and boiler temperature of 122 °C, with the corresponding group-head temperature of 94 ± 1 °C. A total of 21 g of ground coffee (GS = 2.6 ± 0.1; ∼262 μm) was placed in a ridged coffee basket and tamped using a constant-pressure tamper (MHW Flash Constant Pressure Tamper 2), applying 13.6 kg of force. The BR was reduced from 2 to 1.7 following the recommendations of the coffee roaster for better flavour (1 g of coffee grounds yielding 1.7 g of coffee brew).
1:1.7 is a bit short for my preferences (I like longer shots, usually aim for ~2.5); but otherwise that sure sounds like a pretty good double to me!
But I also need my coffee: I'll drink whatever quality coffee is being offered, as long as it's the best I can get that morning.