Whoever designed that seems like they have something against transmission lol.
For me personally: it gets the job done, is allowed by most private trackers, fast and responsive, has a functional webui, and a very vast selection of third party apps (in addition to the cross platform first-party offering)
It's simplicity is kind of its selling point. Only real criticism I have is that it's unfortunate some of the supported features aren't accessible in the first party apps, and especially from the lightweight web interface