That is one of the absolute best tricks for fishing smallish streams for cutthroat. Length of the fly rod lets you reach over weeds and cut banks and put bait right where it needs to be. Very natural presentation. Delivery is more like a soft swing than an actual cast.
Don't see any advantage to using this approach on lakes or larger streams where an actual cast is required though.
In lakes "mooching" weightless or lightly weighted worms works very well- but can be done just fine with a spinning rod. Though I could see a fly rod/line working as well with no real pluses over spinning (assuming you're not really casting).