Both are perfectly valid types of squat but accomplish different goals. Firstly, a high bar squat allows greater depth, but puts far more emphasis on the quads. Low bar squat recruits a lot more posterior chain, allows greater weight (hence why most powerlifters use it), and promotes the 'hip draahve'. Low bar is better for beginners for a number of reasons. Typically hamstrings and glutes are a weakness in novices, high bar simply papers over the cracks. The greater muscle recruitment boosts hormone response, promoting faster/better adaptation.
Of course there are other arguments; personally I just like moving more weight.
Edit:
Another caveat is that high bar squat would be a useful tool to bridge the gap between low bar and front squat. Something I'm planning on doing in the near future as I'm planning on joining a weightlifting club!
Studies have shown muscle recruitment isn't significantly different between the two, the ability to lift more weight mostly comes down to the fact that you're shortening the distance from the barbell to the hip (decreasing the lever arm length) and the ROM is shorter, which makes equivalent loads easier (to squat at least, it's definitely harder on the wrists, elbows and shoulders). Low bar is better for beginners according to the very vocal Mark Rippetoe.
The ability to move more weight is largely unimportant unless it's in a situation/context where moving more weight matters (like a powerlifting 1RM attempt); you can amass equivalent training volume for your legs all sorts of ways and despite never training the low bar squat or training to maximise their 1RM, we know professional weightlifters could easily crush a lot of the raw powerlifting squat records if they were ever that way inclined (they aren't). Even a lot of elite powerlifting places like JTS don't have their athletes even use low bar until later in the training cycle as they transition into strength/taper/peak for a meet, just because high bar (executed properly) is easier to recover from/less stressful on the CNS, more specific for leg strength and has a lower injury risk. High bar builds low bar, low bar does not build high bar, high bar to build leg strength, low bar to express it are quite a common statements too.
Hormonal response between any one exercise is insignificant in terms of adaptation. Resistance training in general is key, and getting better at any one lift mostly comes down to practice, so someone only squatting once a week won't improve at it as quickly both in terms of technique and progressive overload as someone who squats three times a week.
I'd argue most people have weak everything when they start and if anything when watching other people squat, they usually dump the load to the posterior chain on the concentric (knees shift back, hips shoot up) because their quads aren't strong enough coming out of the hole, since the combination of hamstrings, glutes and low back can easily overpower them in any squat variation as there's more total muscle there, and the body will always unconsciously revert to what it feels is the easiest position to move a load, even if it isn't necessarily the best or safest way to get a load from A to B.
