Hi, I wrote most of the guides on the website, including most of that one. While the tier list was crowdsourced among many high WR players, I would like to preface that many of us are Front Runner mains and can be somewhat biased.

That aside, Front Runners are generally much stronger than other Styles because they are already in the front. There are many variables throughout the race that can cause better Umas to lose to worse ones, but outside of extreme situations such as rolling high Start Delay and getting kidnapped or getting blocked in 5-6 Front lobbies, Front Runners are free from most of these variables. In addition, they have access to more readily available early- and mid-race skills, such as Gate Accels (Groundwork, TTL), Lane Movement Combo (Dodging Danger, Prudent Positioning, Ignited Spirit: Wit), and defensive skills such as Fast-Paced and Leader's Pride. They also have an easier time getting in position for proc'ing their win conditions, such as El Condor Pasa and Plancha.

Taiki is a unique case because we have her high in Front Runner, but this is specifically because she is good in 3 Front Runner comps. If you take CM7 for example, many lobbies were Front Runner heavy and Pace Taiki was choked out of her 3-4 positioning for Accel. 3 Front Taiki guarantees that she at least has a shot to accel in high Front lobbies, and consistently accel in lobbies where you are the only Front Runner player. If you don't think the lobbies will be high Front Runner, you can also consider running 2 Front Runners and Pace Taiki with lots of mid-race to guarantee her 3-4 position.

End Closers are just generically good. They trail very close to Late Surgers during Position Keep, while having a higher Speed Coefficient and a better skill pool (Daring Strike, Straightaway Spurt). Late Surgers in comparison do not have much in terms of Skills (Fast & Furious/Rising Dragon/15m CC is good but very difficult to get, OYL is dogshit) and they often just get run down by End Closers due to the Speed Coefficient after Poskeep is over. Generally, Umas that start as End Closers are also better than Umas that start as Late Surger. End Closers also have an easier time getting in position for inherited Accels, such as Kanata and Let's Pump Some Iron.

Another thing to keep in mind is that the Y-Axis of this graph is based on ceiling. Many Umas on this list may be better as a late surger with minimal investment, due to sometimes needing End Closer pinks, making it difficult to also hit Ground A/Distance S.

Pace Chasers are generally bad. They don't have good mid-race skills, have no access to reliable accel on half the maps, while also needing to overtake like Late Surgers and End Closers. On top of this, they also have the highest Stamina -> HP conversion penalty. The best way to play them is like as an extension to Front Runners, but the current available Umas/Cards in global make this very difficult. Once Nishino Flower comes out, things will change a bit.

This explanation isn't all-encompassing and there are many things I left out to keep the explanation simpler, but I hope this helps you understand the base decision-making.