Stores don't have their SCMS plugged in so I can't see if a laser is
worth having.

Here's my main concern: will a pencil mark on a dark colored wood like
walnut (hard to see under the best conditions) be visible under a laser?

I currently just pull the saw blade down (NON slider) to the wood and
align the mark with the edge of the blade. If I get a sliding miter
saw, I'm PRESUMING that while the saw is in front of the wood, the laser
light will shine towards the rear where a narrow piece of wood is
against the fence and will indicate the cutting path without having to
move the saw to the rear and hold it down against the wood. IS THIS TRUE?

Dave