Relaying our inner-most anger about a customer service issue can sometimes be difficult.
Communication is a two-way road. What makes these accounts useful is not their regular updates, but their responses to @s. (@s, in Twitter speak, are users replying to another user. Example: "@jetblue your PA announcements are too loud. jetBlue's response.) It's a visual and traceable example that someone's customer service staff is actually working.
I could name a few airlines I wish would do this.
Then again, they probably know better.