I had the same reaction but then wondered whether the thing that makes work 'work' might help stave off cognitive decline. I.e. At least a few times a week I don't feel like working but, because my livelihood depends on it, I have no choice but to force myself to. On the contrary, if I don't happen to feel like engaging in any one of my numerous hobbies it's easy for me to veg out instead and thus risk cognitive decline.

Perhaps there's some threshold of 'vegging' that isn't obtained if one has enough hobbies.