Hi matey
You are right. Not all aquariums are the same.
A 50% water change weekly for me personally would be ok as I have tested my tap water for fish harming toxins and they are minimal.
Some water supplies have very high levels of nitrates for example. Toxins in an aquarium such as ammonia and nitrite when tested will show as 0ppm. That is not to say there are none but probably that they are too little to register on the chosen test kit.
A cycled tank ideally should have no more than 40ppm of nitrates as prolonged exposure to anything higher can harm the inhabitants. Some tap waters already have levels as high as this so if you are adding tap water frequently you could potentially be adding nitrates. Although I agree that there are essential nutrients in tap water. I would disagree that all supplies are pure. I guess this is why a 25% Change is recommended by most as you cannot always guarantee the quality of your water supply.
Plants will happily consume these nitrates in a heavily planted tank along with carbon dioxide from the fish. Other plant beneficial nutrients such as potassium, magnesium and phosphorus can supplemented if required.
What I'm trying to say is that an established tank should be able to control toxin levels so long as the tank is not overstocked, over fed and with good plant maintenance. Adding a small clean up crew with a small boi-load will also help.
Personally, I would rather let my BB take care of the fish waste and my plants the nitrates. And aid them with small weekly water changes. In the main, what I am disagreeing on is your comment regarding 50% daily water changes are more effective than the biological and mechanical filtration.
I would like to point out that I am not a seasoned veteran in this hobby. I did a lot of research after I owned my first aquarium with disastrous consequences and the information I have gathered since has worked for me. As obviously your method works for you, I guess we can say that we are both doing a good job. My fish are doing brilliantly
Enjoyed your posts bud.