Thalia, Guardian of Thraben, like Kitchen Finks, is a main-deck card in some decks but also comes in from sideboards to fight against spell-based combo like Storm, while also being helpful against pretty much any deck with a lot of non-creatures
(There is psychological value to countering an opposing spell with a Force Spike since they are so easy to play around, yet it's not worth playing around them in Commander because they aren't heavily played, which makes getting your powerful spell hit by Jwari Disruption especially devastating.) As for the rest of the bunch, Silundi Vision is listed as an often play just because you need to be a reasonably spell-heavy deck for it to work
In spite of its multitude of reprints over the years, the rare Bird still manages to hold an $8 price tag
Traditional tutors like Demonic Tutor work alongside Captain Sisay and Captain Sisay to find much-needed effects such as K-9's evasion or the trample effects on Surrak Dragonclaw or Kenrith, the Returned King
And they can be easily countered or prevented by other spells or abilities
