The other 10 times, it's because I want to install some specific app that I already know and I just want to get to the page of that exact app - either through a direct link or through the store's search.
There were exactly zero times where I opened the store with the motivation "gee, I really feel like installing a new app, but I have no idea what it should be... Let's check out the recommendations!"
Yet this seems to be what the entire UI is optimized for.