HN user
Learning the concepts and using SRS are not only not mutually exclusive, they're complementary. There's no quicker way to "grok" a deep technical or mathematical insight than to simply expose yourself to it in a diversity of cognitive contexts. SRS works incredibly well because it generates this diversity as a function of regularly scheduled time. Think of it as entropy generation coupled with heavy reinforcement.
You falsely assume the only 'work' to be done is that immediately aligned with sprint velocity rather than all that done to make someone a valuable contributor in the first place (what your employer is actually paying for). The person who spends ~2 hours a day 'working' and the rest of their day on research, self-education, or more theoretical domains will become exponentially more valuable over time compared the most endurant hamster wheel runner as a function of qualitatively superior capabilities. Smart engineers realize this growth curve and alter their trajectory, benefitting both themselves and their employer long-term.
If two people perform an action with 1/10,000 chance of death, but person A performs it once per year and person B performs it 10,000 times per year, whose life is more heavily dependent on the underlying fatality rate of the action?
You learned using the AOPS books? Don't be fooled by the titles, these books exclusively use a proof-based approach to construct a pretty wide foundation around these topics.