I 100% agree.
I think people use light on 24/7 because they want to (unwittingly) grow less healthy plants; plants that do not have as high of a rate of photosynthesis and rate of growth as plants using proper diurnal (daylength) time, ex. 20 hours max. Plants use night time even in veg to carry out "light independent reactions" (formally termed "dark reactions") such as calvin cycle, circadian rhythm, etc.
Plants grow the most during the night and very early morning hours...by far.
That said, plants can do without a night time, but it's not a great idea.
Not using a night hinders most plants and shows how much cannabis book authors do not understand plant physiology and photobiology. It's really a shame that the likes of Mel Frank, Ed Rosenthall, Jorge Cervanties, etc., perpetuate the incorrect claims that plants do fine when they don't have night. That claim is total BS in terms of rate of photosynthesis, rate of growth, level of plant stress, calvin cycle, circadian rhythm etc., etc.
Plants need night time for the best growth. Plants can grow without a night but they have reduced rate of photosynthesis, reduced rate of growth, reduced carbon assimilate and partitioning, etc., etc., et al.
Also, Ca is transported within plant (xylem) most efficiently during the night IIRC.
Another issue with providing light 24/7 is "photoinhibition" of plants. The problem is the "Daily Light Integral" (DLI), which is the total amount of light (i.e. photons within PAR range) that irradiates the plant per day (as moles/meter^2/day). Too much DLI is just as bad as too much light (as a single instance measurement with Lux, PPFD, etc) in terms of hindering the plant's biological process. Namely by reducing stomatal conductance that in turn reduces the rate of photosynthesis, Co2 fixation, calcium and boron movement into roots, etc.
DLI is a very important factor and one that is lost on most people, sadly. Lumens, lux, PPDF (Photosynthetic Photon Flux Density), etc., are single instance measurements of light. However, we need to consider the sum of light over the whole day, not just for a second. In other words, we should not be using lumens, lux, PPFD, etc., to judge how much light is good for plants unless we only give them a second of light per day. We should be using PPFD-DLI. And while on this topic, weshould notuse lumens or lux anyway, they are not for plants, we should use at least PPFD.
FWIW, here is something I wrote last week about ideal PPFD for cannabis adjusted to a natural diurnal bell-curve of PPFD found in nature:
"Control red to far-red light ratio to limit stretching"
https://www.icmag.com/ic/showthread.php?t=194053
FWIW, I think it's possible to use a 600w or 1,000 watt with far-red blocking film or plastic and still provide ideal (high) level of light (irradiance) per day for cannabis. That is, using the proven ideal PPFD for cannabis (~1,500) adjusted for a natural PPFD diurnal bell-curve over a whole day to find the "Daily Light Integral" (DLI); ex., for a 12 hour day. Thus the ideal (natural environment replicated) PPFD-DLI for cannabis during flowering to reach highest rate of photosynthesis, yield, growth, etc., is 43 to 48 moles/m^2/day. To reach 43 to 48 moles/m^2/day for 12 hours (flowing) we need to provide ~1,000 to 1,100 PPFD [5].
Using peak diurnal PPFD of 1,500 adjusted with an average PPFD diurnal bell-curve from a high irradaince location (ex. Hawaii on relatively cloudless day maxing out at 1,500-2,000 PPFD) to find PPFD-DLI is the best method to measure lighting for a garden. That is, short of using PPFD weighted with K.McCree's Action Spectra of Photosynthesis once McCree's work is corrected with the new info about high irrdiance white light sourced green light providing as much quantum efficiency as red light (i.e. driving rate of photosynthesis as well as red light).