Tiers are just a ranking on how often a character is gonna win in general.
If someone picks Valk or Kokonoe, lets just say if I already picked a character I know is eh against them i'm gonna sigh and not enjoy myself, but that's the game.
They're top tier because they're good, but just picking Top Tier doesn't mean instant win, if you have a dominating victory with a top tier that isn't Kokopuffs, then you clearly did put in a lot of work.
Kokonoe though....jury is out on that one, not saying playing the character takes no skill, but i think this is just my salt speaking.