Waifu4Life: You can't even use the word light since these guns to not sense light. They work with one of the following:
1- Motion sensing (the less accurate kind) which is what this game uses on the Switch
2- Motions pointing which can either require:
a) You to follow a visible or invisible crosshairs in case of a basic set-up like a Wii sensor bar
b) You can shoot anywhere without crosshairs because you have sensors all around your monitor
That last one is the closes to what classic light gun feels like while still not being an actual light gun.
Actually the Sinden lightgun has a camera in it, so does indeed sense light. In fact, the majority of the time I spent setting mine up was playing with the light sensitivity options. So that it can "see" the screen and not be overpowered by other light sources.
It takes over the mouse, which can be hidden though a macro for most games (if you bother setting it up), as opposed to be a separate device though. With the mouse hidden, you shouldn't see crosshairs with the majority of games.
It may not work in the same way a traditional CRT style lightgun would and setting it up is a real pain initially, but it is a indeed a "lightgun" in the sense that it does see "light".
Side notes for anyone interested in the Sinden Lightgun:
I ordered mine in the summer of 2021 and it came in Feb 2022, so there's a bit of a wait time.
There's a fairly active small community creating patches and maintaining a wiki (for example, I just read on the steam forum that a patch for House of the Dead Remake was released that fixes the Sinden issues[Single player only at this point]).
In general, 2 Player support is only available with a few programs.
Setup is not as simple as plug and play, you will spend a fair bit of time initially with the software and in most cases tweaking the programs/games.
Once set up properly, it's very accurate and fun. Wish I had gotten the recoil pack but didn't realize that it could be turned off through the software.