Might just be me, but I genuinely wish there was reliable data on everything like this. I'd love to know that someone did a proper study, found that it's not damaging to the knees if you're between BMI such-and-such and run between x and y kilometers every day, that it has health benefits a, b and c, but that of course you have to invest time amount z which one might use also for swimming which then has another value. Then you can just weigh what you enjoy more against the benefits.

Lots of people do things they know is bad for them, more data hasn't stopped anyone from making their own decision, while I do see the potential benefits.

The argument you're making seems to just dismiss the idea without substantiating why it's not important to try and factor in all the factors to reach a conclusion.