There aren't many market options for the G42. Viridian, Streamlight, and laserlyte are the only 3 I have seen. I'm mixed on the viridian, as I don't really want it to come on when I draw it, but of course, it can be used as a manual.
I personally don't like all of the strobe features on weapon lights. I prefer to have one either only strobe, or only be on, but would rather not need to toggle between activation styles to do one or the other. I'd rather have a handheld strobe only and weapon light always on, or vice versa.
Having a light on your pistol doesn't mean you have to use it, it only means you can if you need to. If you're the type who trains to function one handed; reloads, malfunction drills, etc, then you should be equipping a weapon light too.