Over the last few months, I've been digging into performance problems with a high throughput service that my team owns. I started working on the problems in my own time, put out short and medium term improvements that legitimately avoided operational issues, and started developing an alternate architecture that should meaningfully address the problems for the long term.
I've learned new things and made improvements that probably wouldn't have ever gone in otherwise.
I've spent my whole career being frustrated by the pile of low severity bugs and performance issues that "I could fix that if I could only justify putting a couple hours into it!". And now I can just fix all those. Nobody is going to question my use of time to write prompts and do code reviews of those things, when I can to my "real" work simultaneously.