Keyboards That Do It All
Electronic pianos, samplers, etc., often come with built-in rhythm units that include drum samples. Click a switch, and a drum groove starts to play, and you can adjust its speed, the style (jazz, funk, reggae, etc.), and other options. Some keyboards come with one-touch chord accompaniment (play a C note, and hear a C chord, for example) or automatic bass-line generation when you play a chord. Still others have MIDI inputs and outputs for connecting to computers or to other musical equipment such as synthesizers and samplers. And finally, some offer a built-in sequencer, which is a small computer devoted to digitally recording and playing back notes that you perform on the keyboard. These are fun features, and they can be very useful, but they aren't necessary to learning.
But should you automatically "just say no" to keyboards with these features? Nada. Here's why: Once you get your skills developed to the point where you can learn and play actual songs, accompaniment can be more fun than practicing to a metronome. The drum unit in a keyboard will keep the beat as accurately as any metronome, but instead of going "tick, tick, tick" like some boring clock, your keyboard will be providing things like kick drum, snare drum, cymbals, and more, making you feel as if you're in the fun zone instead of the drudge zone. Chord and bass accompaniment may not be nearly as useful, although they can give you some ideas when you're working on songs later.
A built-in sequencer might be pretty useful, however. Turn it on "record" while you're playing scales or chords or entire songs, and then listen back to how well you performed, or didn't. It's a good way to find where you might be having some difficulties, and provide you with an opportunity to catch your mistakes. While you're actually playing, it's hard to evaluate yourself. This makes it pretty easy.
Until you have the basic playing skills under control, the auto-accompaniment with drums, bass, and chords may be handy for others in your family who either play already or who just want to fool around with the keyboard. Someone who knows how to play well and who understands the accompaniment features can make a lot of music come out of a keyboard, and in fact there are instructors who teach people to use these features and make them sound good.
The bottom line: If your family is at different levels of playing experience, or if you feel you really need auto-accompaniment and other similar features on a keyboard, or the keyboard itself feels great and the extras just happen to be there, then get that keyboard instrument. Otherwise, you don't really need these extra features (even if someday you might want them).