Is it still thermally stable after a low-speed journey through a long (? Hard to say how long it is, or if you just plonk it into an open kettle of water as there are only close ups) narrow plastic tube? And what about cold water already in the tube?
If thermal stability is important enough to make such an advertising claim, you should probably show a comparison of input temperatures where the water meets the coffee over the course of multiple cycles against a representative competitor. With actual data rather than stylised cartoon graphs like in TV adverts for washing powder or whatever.
Woolly claims like that without clear evidence really make sound like audiophile woo territory, which would be a shame if you've actually done the research!
Thermal stability is arguably one of the most important aspects of espresso machine. If the water in the espresso machine boiler is sitting at 95°C, by the time this hot water reaches the group head it will lose some of the temperature. Lose 2°C and you're good. Lose 5°C and you still might be good but already at the edge of getting the crap out of the machine. Lose more than that and you're not gonna want to drink it.
Traditional E61 espresso machines whose water boiler is at ΔT cm's away from the group head, solve the problem of temperature surf with heavy duty pipes, boilers, isolation and materials to keep the temperature loss at the minimum.
More modern espresso machines place the water boiler just above the group head so they're basically solving the problem other way around: keeping the ΔT at minimum so giving no or minimum space for temperature loss.
As for this design, I am not sure how does it solve this problem.
In addition I would need to some justification for the idea that water stored in a clean tank without access to light is somehow worse than fresh out of a filter.
If thermal stability is important enough to make such an advertising claim, you should probably show a comparison of input temperatures where the water meets the coffee over the course of multiple cycles against a representative competitor. With actual data rather than stylised cartoon graphs like in TV adverts for washing powder or whatever.
Woolly claims like that without clear evidence really make sound like audiophile woo territory, which would be a shame if you've actually done the research!