I'm not arguing that 30 minutes of exercise isn't healthy - the parent post to which my comment responded was two hours a day. I'd be dead in a week if I tried that because my spouse would kill me.

So much exercise advice is disingenuous: 30 minutes exercise != 30 minutes out of one's day

Change cloths, warm up, exercise, cool down, shower, change clothes: there's significant overhead even if one doesn't have to travel to the gym.