Form factor isn’t unique- mono led boards existed before “ white led boards “ hence HLG pretty much breaking ground back then - a progression from COBS . Which they began building and selling under Northern Grow Lights then they began building original QB 304 ( LM561c ) and Nichia. Original boards have hand written Vf numbers on them. Back then you had to try to buy a “ pair “ that was close in numbers.
Form factor is similar to old led mono diode ( epistar and similar ) most of those were shit as single diodes ( ir ) would burn out or entire strings.
The only real advancement in board design will be mixed or custom spectrum boards. Wider spectrum or UV / IR combos even more efficient red / blue panels ( blurple 2.0 )