I completely agree that listing recently played by others is useless and annoying. And it doesn't even work as possible advertising in my case, because that's not at all how I pick games, and I'll just ignore it.
As another annoyance here, when you resize the window, they favor the "Recently Played by Others" over the "Recently Played be Me", so that you end up with more games showing in the "Recently Played by Others" list. You can get more in "Recently Played by Me" by making the window wider, but they always add more to "Recently Played by Others" first.
However, I would point out that on the top right of both the "Recently Played by Me" and "Recently Played by Others" sections, there are little arrows that you can click to scroll the list left or right. So, while it may not be immediately obvious, you can see more than just 4 or 5 games in each list. So, it's not _quite_ as bad as it first looks, but I really wish that they'd just get rid of the "Others" bit entirely. It's just taking up screen real estate. I don't care what anyone else is playing. And not a one of the games currently showing up in the "Others" list on my PC is even on GoG, so I don't see how it even benefits GoG for it to be there.