While you don’t need squats for leg growth, they are certainly beneficial and arguably are best for building a foundation of strength that will help you progress on other movements.
If you’re having lower back pain, I would try front squats or heels-elevated front squats. When my lower back is sore, front squatting tends to be totally fine whereas back squats suffer due to the core/low-back involvement.
Leg press and hack squats can be great alternatives and potentially even better for hypertrophy if used correctly. [/quote]
Agreed, generally the more upright you can keep your torso while squatting, the less likely the lower back is going to be the limiting factor. Front squats allow you to do this nicely, and pretty much totally remove the possibility of rounding the lower back forwards or performing a “good morning” as the bar will simply roll off your shoulders if you try to do that on a front squat.
Also, since the OP’s main goal is bodybuilding and not powerlifting, then he first has to decide what muscles he is primarily trying to build with his squats and make sure they don’t cause him any pain, supposing his form is correct (like Bonez said) and therefore not necessarily get locked into the idea that there is only one way to squat, or that say back squats are automatically better than front squats or vice versa.
For instance Tom Platz squatted differently than Matt Wenning from that video above suggests, but Platz was primarily concerned with making his legs bigger, while Wenning is primarily concerned with moving the most weight possible from point A to point B, and back to point A. Both styles of squatting are technically correct, but call on different muscles to greater or lesser extents and produce different results. Also individual variances in terms of limb/lever lengths can cause some styles of squatting to be more of less comfortable for different individuals.