This is actually a good question and I can argue both sides of the debate.
I believe that everything is situational and one size does not fit all.
As a personal example, I have hard water and am not too worried about Ca/Mg. The tank is at least 75% Java Fern with a bunch of floaters and Ambulia. Med to heavy load of guppies and some cories and I overfeed. Med light and co2 , blah blah blah. The tank had been running for about 15 years, with 3 - re-dos, the last one 3 years ago.
The end result is consistent 40 ppm N and 2 ppm P, pH of 6.7, tap is 7.4.
Sooo, why would I fertilize or do 50% weeekly water changes in that tank? I don't. Top off maybe once a week, 20-30% water change a month or two. Check TDS here and there.
We preach stability above all. What a 50% water change would do to that tank? Most likely nothing, except a higher water bill.
My point: don't blindly buy into somebody else's dogma. Instead think, observe, adapt.
A bare bottom Discus grow out tank? A rotala macrandra tank with 200++ PAR and white drop checker? Different beasts, different training.
Courtesy * Integrity * Perseverance * Indominable Spirit * and Self Control
Tenets of TKD