Personal opinion;
Money or no money, if you can make your job easier, faster, better, why not?
I learned to write autolisp for me, not my employer.
If you want to learn it then you need to write code every day. It doesn't have to be a massive application, just anything, tinker with it if nothing else. I get to work on average 1-1/2 hours early every day just so I can write code, and I've done this for years. It's the best time for me because it's quiet and my head is cooled off from the previous days coding. Mind you I'm not at the level of Mr. Madsen, Mr. Puckett, Mr. Bethel or Mr. Blackie just to name a few around here but I can whip up a quick time saving app when I need one. And that to me is the knowledge level you should aim for. So what are you waiting for?
(defun write-lisp (when)
(alert (strcat "When should I start? " when))
)
(write-lisp "NOW!!!")