I agree.  It's really all just a marketing ploy.  You have a drug and it mainstream effects, and then it's other effects.  But who would want to take something to cause dizziness or headache, hence it's a side effect.

Don't believe me?  Ok.  You've heard of the term withdrawal effects right.  It's what happens when you come off an addictive drug, street or legal. Now, because of the stigma connected with the term "withdrawal" effects (sounds like you're quitting heroin or something) these effects in medical drugs are now call "discontinuation" symptoms.  Oh that sounds a lot nicer... and with no heroin stigma. Plus it sound more "normal", because you are discontinuing the drug.

It might seem only like a mild change to some of you, why make a big deal about it.  But a lot of power is held in words, and people will continue to slightly tweak and tweak terms so they sound more flowery.