Well, tiers are based on just ratio of good match ups to bad match ups, and how good or bad they are.
Lambda places well tier wise because she just destroys certain characters, and generally good match ups against a great number of characters.
But in tournament play she just isn't as viable despite tier placement, since she just features glaringly bad match ups (according to the chart) against the best (and as a result, most played) characters in the game.
And there's simply no way to build a tier list from scratch, that could account for such realities when deciding tier placement, as far as I can figure it, without being probably misrepresentative (as in, you can't arbitrarily do things like, having a bad match up against Bang and Litchi do more damage to your placement than having a bad match up against Lambda, as in Arakune's case).
Because the simple reality is, if SBO was not teams, and it still had like 80% of the entrants being Bang or Litchi, those like 2 Lambda players are basically doomed. While Arakune, for example, profits, because one of his bad match ups becomes very improbable so far as it coming up. While Lambda has a 100% chance of running into her worst match ups several times.
But even with that reality, a tier list just can't be built to reflect it. That is "how" a tier list could fail to reflect reality.
The only alternative method would be to build tier lists not from match up knowledge, but just from corrobating statistics, like the Scruber Smash Bros. community did at some point, if I recall properly. But that simply reflects tiers by assuming the performance of characters in tournaments reflect their actual strength.
EDIT: As an addendum, the match-up based tier lists that worldjem7 builds aren't going to feel accurate competitively, when the master format of the game is to play double elimination.
If fighting games tournaments were played round robin style or swiss tournament style, this format of matchup/tier charts would feel significantly more accurate, probably, assuming a half decent variety of characters being represented (ideally equal numbers of every character).