When you pull up a lot of ADA AS and replant, that makes quite the mess.
Also, staying on top of things has many benefits.
Those are why we do __any water changes__ (mostly).
ADA suggest weekly large water changes, but we do not see anyone complaining about their dosing.
I find that curious. ADA gets a free pass on that topic and rarely even a straight answer.
I also do not do this many water changes on tank which receive less gardening, like the 70 Gallon Buce tank, maybe once a month there. Dosing is the same otherwise.
Dosing is NOT why you do a water change, but if you want to use frequent water changes + dosing to keep a certain range, it's much easier and simpler than dosing and testing.
But this assumes that some ppm of a specific or a set of nutrients is bad(for fish, plants, etc) when at excess values.
The other issues when you uproot and move things around, trim etc, is the lowering of O2. Water changes remove the dirt/dust and adds plenty of O2 back.
If you do not pull up a lot of stuff etc, then a water change is not really required. Still, lots of water changes cure most issues folks often have that have trouble, algae, poor plant health etc.
It is simply put: the best advice to give broadly to aquarist. Simple, effective and keeps the tank very clean.
Dosing is a minor part in all this.