I think it's a pretty great platform for the price. It lacks the bells and whistles of something like multicharts but it's backtesting for single instruments is not bad. It has probably one of the best charting packages on the planet for $14.99 and is linked up to a community forum for top tier shitposting. I don't personally use it (futures spreads and all...) but just about everyone I know that trades uses it. The level of convenience, lack of needing to install some bullshit platform-and-service-pack-dependent software from a company that still develops like its 1982 is worth it in every single way. Recently they've really added a ton of broker links and are working on more. They will quickly consume the overall market for anyone but the most picky of traders. Once they support option chains the current big swinging dick in the field of great UI, TOS, will get completely btfo. I think you really need to quantify the sentence "it does so many things wrong I don't know where to start" because you are certainly in an extremely small community of active traders that don't think it's the greatest thing since sliced bread.
Actually it ain't so bad. Charts are clean. Comes with enough bells and whistles. It offers pine script (watered-down python) for those who might be interested in automation. Definitely the next best invention to Kool-Aid.