I think they’re saying that you could say “I’m going for a smoke break” at work and it was at least tolerated. I don’t think you can say “I’m going for a walk” the same way.
We had 3pm coffee club at a previous job. It was great. Had our own slack channel(public). As the minutes counted down people would post gifs counting down (/giphy 4, /giphy 3). Most of the dev team would go. We’d go a heavy coffee shop. The talks there and back were great.
It has varied a bit depending on the timeline, but: Going out for a walk (or to just change environments and very passively stare at nothing) has been less socially-acceptable than going out for a smoke, in my experience.
One of these things is weird, or perhaps inducing of ire ("How dare he just go outside when he feels like it! What is he even doing?").
The other is, at worst, both understandable and disgusting ("Of course he's out there again with that filthy habit!").
I've worked a number of places where smoking on site wasn't allowed, and it was well accepted that if you wanted to just disappear for 30 minutes once or twice a day no one would care.