This is a movement that we used to do daily to poop, from the time we were able at about age 1, until the time we died. The invention of the toilet ended that. Many of us are no longer able squat that low due to a lack of flexibility, or we can’t get up from there keeping the trunk parallel to the lower legs (chest higher than the butt) on the ascent.
The usual cheat is to lift the butt up first so the trunk is parallel to the ground instead of the lower legs, and then straighten up. If lifting the butt first is the strategy being used, that indicates a lack of strength in the front of the thigh muscles (quadriceps).
Being able to do this movement correctly ensures adequate slack in the myofascia which would likely reduce the incidence of low back, hip, knee and ankle pain.
One would have adequate strength and range-of-motion to do most day-to-day activities, like climbing stairs, getting out of chairs and even low car seats.
In our humble opinion, being able to squat all the way to the floor with no added weight is far more useful in terms of improving function than squatting to the point where the thighs are parallel to the floor with added weight. We know many people that can do half squats with lots of weight, but are not capable of squatting to the floor with just their body weight.
We would not advise squatting with added weight lower than one can keep the back neutral. A flexed (rounded) spine under load is more vulnerable to injury.