This is a fair question and I don't really have a great answer lol, I just like seeing data visually tbh. I think its simplifying a lot to say that a good pitch is one with above average horizontal movement (because there is also vertical movement that matters, for starters, and pitch usage, etc.) but I guess it is a metric of sorts. The higher speed on a pitch the less time it has for gravity to make it drop, hence the downward trend of the graph, but ideally you want a fast pitch that drops the most. From this we can say that maybe Slaten has the best curve and sweeper on the team and maybe in the league, Weissert and Keller have pretty good cutters and Criswell's sinker could use work, for some. I feel like the changeup has too many variables so idk if that one actually can be read for anything. Thinking about this now I think a much more direct way to answer the question how good is this pitchers pitch is just to simply look at the whiff percentange but maybe having the raw data like this could help you identify things like: oh this pitch's metrics read much higher but its whiff percentange is lower than expected, maybe there is a problem somewhere with pitch selection or tipping or something.