As a software engineer with actual knowledge of the cost of code maintenance this comment hurts me. All code can have/cause bugs, interaction poorly with other sections of code, can break in the future and requires you to maintain tests. The leaner your code can be the better. You have to weigh the value from that 3% usage against the cost.
I'm sure I will get nothing but downvotes, but it needed to be said.
Surely Google has in mind software stability when they add complex features like a Duolingo clone and at the same time they make sure that nobody actually use it by implementing it as a geofenced Easter egg hidden in the Google search app