I am talking about barbell back squats just so were clear. When you fail in the squat movement your back buckles not your legs. So when you think your smashing your legs your actually smashing your back even more.
While if you do a split squat correctly your training one leg at a time so the one leg will fail before your back. 2 legs is likely to beat your back and your back will fail.
It's very difficult to do a back squat perfect some would say impossible. It's also very difficult to do a front squat wrong so I prefer those. But optimally split squats.
It also comes down to risk reward and sports specific. The risk reward ratio for a back squat defiantly isn't there for the average person. But someone who competes at skiing is going to be squating as there main workout despite the fact it's probably not great for them long term.
Even top nfl and nba teams are using up to 3:1 ratios in favour of deadlifts over squats. And pretty much all favouring split squats over back squats. But deadlifts aren't something id recommended to anyone without being beside them 1 on 1 for the first few sessions. And I'd built up to it. So I didn't recommend it before.