Jocko Willink posts a picture of his watch during his workout every morning, usually in the 4:20 to 4:30 range.
I can see someone doing this and posting it online to keep themselves accountable.
Would you post what time you worked out everyday? Would you post how many hours you worked today? Would you post how many calories you ate today? There is a reason why this isn't a common way for people to use the internet.