There are many ways to play OpenTTD. There are tons of settings; you can also load extensions, from AIs to NewGRFs. They all modify how the game plays.
From a developer perspective, we don't actually know which settings are heavily used, and which are never used. As such, we often find ourselves in a discussion about whether something is actually useful. The people we talk most about, are not our average user; as it goes, the most vocal people are not the commoner, but more likely the niche. And although we like to promote as many play-styles as possible, it is easy to focus on those vocal people, instead of the 90%.
From an AI / NewGRF perspective, we don't actually know how many people play a game with an extension. As such, it is difficult to judge which extension is actually "popular", and which extension is never really used. This means it is tricky on BaNaNaS to suggest any content.
For both this system is designed: an opt-in automated survey. It is designed to be privacy friendly, and to be as transparent as possible. Anything we do with the survey results can be found on this website.