Let's take the questions one at a time:
Accuracy - Very good.
Distance - Not great, it's a red laser and if you couple it with their TLB-1 target box, it's better to use indoors since daylight washes out the light.
Ease of Use: Quite easy, drop the cartridge into the chamber. You don't feed it from a magazine as you would a snap cap. There is no rim so to get the cartridge out, you use a pencil or a wooden dowel. If you have a double action pistol, pull the trigger and get a flash. If it's a single action you must either pull the hammer back or in the case of a striker fired design, pull back the slide far enough to load up the striker.
For a single action pistol, the cocking requirement between trigger pulls kills lifelike scenarios.
The biggest use is near immediate feedback on if you are causing inaccuracy due to trigger pulls. Since there is no bang or muzzle flip, it can't tell you about bad reactions to recoil. It is a great tool for 1st shot placement say drawing from a holster. Where you thought you were aiming and where the shot would have landed may be different stories.
Can't tell you about how it would work with a Rangemaster system, don't have one. I do use this on some paper targets where I have put a 1/2 inch circle of reflective tape at the center of the target. When I hit that, I get instant feedback in my sight picture. I use the Laserlyte 3 to 4 times per week, the cartridges have for the most part replaced my snap caps.