IR is over 750nm wavelengths, these new IR diodes are 730nm so don’t generate heat like you think they do. The sun generates IR across a broad spectrum, the 730nm IR is part of a wave length that has very good leaf penetration. For example; IR at 730nm tricks lettuce grown indoors into thinking it’s in the shade, which increases its leaf mass (desirable as we eat it). The reason it thinks it’s in the shade is because a higher concentration of IR below 750nm passes through leaves in trees/foliage above it.
There are some studies that are now looking at the relationship between % of 700-750nm wavelengths vs height of plants and how broad their leaves become. Early indications suggest there is a correlation.
When winter is coming and the suns light has to travel through a larger volume of air, wavelengths are slightly stretched out as they pass through the atmosphere which causes a small shift to the longer wavelengths, producing higher concentrations of red, far red light, and IR which is why there is evidence this gives flowering hormones a solid signal after flip and reduces ‘first sign of pistols’ by a couple days.
While the jury is out on whether these diodes are worth the money, if you go get a unit, try to get one where you can switch off the IR separately, so you have a bit more control.