The counterpoint to this is if you aren't specifically assigned tasks you're basically expected to go through the backlog to hunt for things to do. In most companies the backlog is never empty and so you don't really get any time for any of these ancillary tasks. This is part of the reason performance optimizations and other improvements never get done. PMs are encouraged to stuff backlogs full of nonsense related to new features because that's what the people up top want to see. When the reality is, allowing your engineers even 8 hours of unstructured time a week will often produce better work.
The exception to this rule of course tends to be the top of the ladder (senior principal, whatever) who generally get to do whatever they want as long as it's company related. 99.99% of engineers will never reach this point, however, and so the vast majority of these high performers are subject to the tyranny of JIRA and it's subsequent negatives.
The exception to this rule of course tends to be the top of the ladder (senior principal, whatever) who generally get to do whatever they want as long as it's company related. 99.99% of engineers will never reach this point, however, and so the vast majority of these high performers are subject to the tyranny of JIRA and it's subsequent negatives.