What department? I was in Search and used that knowledge all the time, and also did rotations on GWS, Google+, and GFiber. Certainly I used less of that knowledge for GWS (where everything you need is in-process) and for GFiber (where I was working on marketing & customer signup - the job req for this was actually different, and both interviews & job duties were much more like a traditional SWE job in other companies). But even Google+ needed a lot of algorithmic complexity knowledge; G+'s scaling needs are similar to Twitter's, and we know how that went.

Perhaps it has changed as well; when I left (2014) they had just started encouraging engineers to focus on one particular task, with the architecture already defined, while when I started (2009) there were still a number of problems of the form "here's a feature we want to add; here's the data we have available; how can we build it?"