For us WDW the monorail is transportation and DLR, it is more of a ride. It goes from a stop in Downtown Disney to a stop in Tomorrowland- that is it. It goes past GCH, but it doesn't go "through" the inside like the Contemporary, and it doesn't stop.
If you don't mind not walking down Main Street and want to start your day near its stop, if the line isn't huge it is a good option coming from the DLH. You scan your park ticket at the station where you get in line to get on the monorail. So basically you have "entered" the park once you scan in at the station. Back in the Max Pass days, if we were not getting to the park at opening, we would do it so we could get to booking our first max pass for the day as you had to scan in to book.
You can also take it from DL to save some steps to DLH-- BUT if you have to walk through the park to get there you aren't saving many steps, and if the line is long it would have been faster to have just walked to DLH. There have been times I have just wanted to ride the monorail- and DH stands in line complaining that we could have already been back at DLH if we had just walked.