You may have misunderstood something someone told you or something you have
While deadlifting is indeed one of the best exercises for building muscle in
the full body, specifically the legs, it is just like every other exercise with
respects to intensity.
If your intensity is great you will perform the exercise less but to say that
dead lifting one time a month with heavy weight (for powerlifters 2x body weight
is actually light) will help you build muscle is not entirely true.
If you really want to excel in the deadlift, you should perform it 1 time per
week, 2 max. What you described in your question, (heavy or close to
maximal sets) should only be performed maybe once a month or once every 2 weeks
to allow your body to recover.
Your original source probably meant what was just described. If you
have back problems, try to avoid sets of above 8 reps as the back tends to give
out before the legs, shoulders, etc.
Dead lift is more of a full body type exercise (low back, upper shoulders,
grip) as it does not really isolate the legs. It is a great exercise but
if you had only one exercise to do and you were trying to build your legs,
squats are superior.