I did land a job making applications for an HFT firm and while I don't think that being able to implement data structures or write my own algorithms is necessar

I did land a job making applications for an HFT firm and while I don't think that being able to implement data structures or write my own algorithms is necessarily what will allow me to keep this job, recently I somewhat regularly use the skills I pick up doing competitive programming exercises in my workplaces. Therefore, my answer to your question about whether it will help my performance in a measurable way is: yes.