Amazon Marketplace -- What Constitutes "Expedited" Mail?

Since I have Amazon Prime I tend to prefer ordering items eligible for that, but sometimes there's just too good a deal to pass up that isn't Prime-eligible. Recently I've made about three-four purchases from Marketplace people, and a few offered "expedited" shipping, which charges you Amazon's flat rate of about $5.

However, all three people I've ordered from sent my package First Class Mail. I guess to me, that doesn't seem like Expedited -- the USPS does estimate timing of 1-3 days average, but I've had packages take longer to get there First Class (depending on where it was sent from). Not to mention I can't imagine Amazon meant that by expedited -- they charge a $5+ flat rate for it!

Would you all consider that 'expedited'? Am I making a big deal out of nothing? I guess I expected Priority Mail at that cost. I don't see how sending First Class expedites anything, unless using the logic that they would have otherwise sent it Media Mail, which is admittedly slower, but on items like CDs, is rarely any cheaper to the seller than 1st class mail. Just seems a bit annoying to have spent $10 extra on three packages to get them as fast as I would have had I chose standard shipping.

yeah whenever i sell books and people want expedited i send it first class rather than media mail