Stereo input mixer question

[abbazabba]

Newbie question:
I'm looking to buy a mixer, most likely the much recommended Soundcraft M8. However, I am on a budget and that leads me to look at the M4 and wonder, I'll rarely need the stereo inputs (I think) so why can't I use them as if they were mono?

(unrelated question that anyone can choose to answer if they want to/know the answer: quoting an article I read, "A small mixer will also have a built in mic-pre that you can you use for your talkback mic." Do the Soundcrafts have this?)

[sdelsolray]

You can, as long as you feed both the left and right inputs for the stereo channels with the same mono signal. This will require some cabling/adapters. Also, the eq on the stereo track on the Soundcraft M Series are treble and bass only, whereas the normal preamp mono inputs have a sweepable midrange eq in additional to treble and bass. There are no direct outs for the stereo channels.

[abbazabba]

Um, what do i need the direct outs for exactly? or rather, what do i lose by not having direct outs? I really appreciate the help.