Apologies, Can't link as I used a pen name for freedom of expression. So far nothing attaches me to the book.
Yes I do use the skills, on email daily for example. I understand punctuation a bit better and many word definitions are clearer. As a programmer I could already touch-type. I repeat myself less and edit down my copy removing redundant words. One concise sentence is better than saying the same thing 10 ways. I don't have as much anxiety or stress in general as writing things down gets it all out and helps you understand yourself better. Turning mentalses into logic. You may even find you logically disagree with how you 'thought' you were thinking. This is very resolving. You also learn a lot about the subject you are writing.
Yes I had a job, yes it did affect it. For 2 years writing became my evening hobby instead of coding. Sometimes it felt like I was deviating from what I should be doing. I ignored those feelings. Peers that didn't know me very long judged me as not being into my vocation (something I normally pride myself on.) I felt this affected my stance in the team. But I had more to gain than other peoples opinions. I've been a generalist coder for 15+ years so was a decade ahead of many of them and could afford to drop a gear.
I admit to cheating in the editing phase. After 11 months of editing I'd almost re-written the whole book. I realised like painting, writing is never finished, only left. This is partly because you're always changing. I tried modafinil, wrapped up in a few weeks and moved on.