I would do that anyway, because it is always better to distribute 430 watts over 4 PCI 8 pin rails in the power supply unit than only over 3.
Nevertheless, the maximum of 450 watts is not quite right.
So the card draws up to 75 watts directly from the PCI slot on the motherboard and then 3 X 150 watts from the 3 connectors, that's a total of 525 watts maximum.
On most cards, for example, the fans are powered from this motherboard connector to better distribute the load across all available connectors.
In the benchmarks I found quickly, the very rare and very short watt peak was always well below 525 watts, rather in the 470 watt range.
In the benchmarks, only 9 additional watts were even sucked out of the PCI slot, because the card never produced a peak long enough to draw more than the juice for the fans from the PCI slot.
Oddly enough, there are benchmarks that have peaked at exactly 450 watts, which leads me to speculate if this new 12VHP connector and the PCI port aren't running on the same circuit at all. But item, the average at 4k was 430 watts and whether now for 10 or 12 frames the card runs at 65 instead of 71 fps under raytracing because it peaks at 450 instead of 470, you won't notice.
But, nevertheless, if a 4-fold adapter is included, then you should also equip it completely, because otherwise you have a dead plug on which 450 watts of power lie during a discharge, which can mix up the inner workings of your PC pretty badly.