This is a well-known fact in the keyboard world, and symptomatic to the great divide that runs down the middle of the product ranges: there are serious keyboards on one side, and there are home keyboards on the other side.
Home keyboards start with 30.50 euro playthings, battery-powered, rotund abominations made from cheap plastic that are supposed to make great Christmas presents for children. Actually, anyone who gives a child such a horrible 32-ultra-mini-key toy should be shot, quartered and then really hurt. Next come entertainer keyboards, a/k/a portable keyboards a/k/a arranger keyboards, things from 155 euros upwards, with a 61-key keyboard and a built-in crappy sound system. They're all basically compact descendants of the venerably cheesy home organ: machines generating 'styles', automatic accompaniment you play along to. The speakers don't get much better with increasing price, though the sounds and styles do (believe me, those prices do increase a lot -- top-of-the-line models come in around 2500-3000 euros. There's also the Wersi Abakus, the Mercedes of live muzak, costing more than 8000 euros with all the options.). Except for one-man bands, these things aren't of much use to anybody, though some people are deluding they're the right instrument to teach music to youngsters. The opposite is true; if you want to learn an instrument, learn to play something where they teach you how to use both hands.
Serious keyboards aren't called keyboards, actually. They are called synthesizers, musical workstations, stage pianos or stage organs and they never comprise built-in speakers. They come at all prices between 600 and 5000 euros and are designed to be hooked up to a P.A. system, a keyboard amplifier or a Leslie cabinet. There is no automatic accompaniment built into them as they're supposed to be played either with a band or by someone with a decent musical education. They may include sequencers or arpeggiators, but those differ from automatic accompaniment in that they don't replace musical invention; they're just technical support.
(Actually, there are now some 'professional entertainment workstations' such as the Yamaha PSR-9000 Pro or the Ketron SD1. They're essentially huge, expensive home keyboards without speakers. Shame on them for blurring the line.)