True, but for years if you owned a Japanese vehicle you had to buy a special coolant that was compatible with aluminum. The Japanese standardized aluminum use for heating and cooling systems long before US and Euro manufacturers adopted it. At the time, copper was still abundant and Japan had to import it at great expense.not sure why there is a hang up on "Japanese" radiators and water pumps.
Most radiators in today's water cooled engines are aluminum with plastic parts as well.
The silicate free coolant was developed for aluminum radiators, not just the Honda ones.
Less than a 50/50 mix of water and coolant may sound intelligent but if it made sense, I believe you would see wide spread use of it.