It's not an ad¹. A lot of humans navigate that way, for many reasons. Google has done research on that through the years. Landmarks might be easier to spot and are an useful confirmation that you got the turn right. Do you never ask yourself if you just made a mistake? Perhaps you got distracted by a passenger, another vehicle or a pedestrian.

The street name you are turning onto might be not as visible because the sign is small, covered by a large truck or not well lit at night. Key Bank is probably harder to miss.

Or there might be no street name at all, which is often the case in places like India, where Google has been testing this for many years. In that case you have no choice but to use landmarks.

¹Or, at least, one that you can purchase now. It might happen in the future, but of course they'd have to be careful when rolling this out. Imagine if they used a business that is not very distinguishable and thus not a real landmark. That would diminish Maps' utility.