I do believe it is bluetooth, though I am not sure how you would pair other devices? The originals have to be docked on the unit and this one you plug into the USB-C and it pairs. There are quite a few 3rd party controllers out for it already, but I wanted an actual Nintendo device despite the price. I also heard the Switch controllers work with the Wii.
8bitdo controllers are excellent! The SNES30 copies the original SNES form factor extremely well. I use these for my retro games, and I also have an NES30 that is almost a hybrid NES/SNES/Analog Stick controller.
I do understand wanting the 1st party controller, though. And, I can't say how well the 8bitdo works on the Switch, especially with the Switch games vs retro games.
With all of that being said, I did dig up some reference info for anyone else that may be interested.
You will likely need to update to the latest firmware to get these to work on the Switch, but that is likely a good choice for any modern controller on any console, and the 8bitdo FW update was quick and painless.
https://www.imore.com/8bitdo-controllers-now-work-nintendo-switch
To pair your 8Bitdo controller to your Nintendo Switch, Press and hold Start + Y on the controller for one second until the LED light blinks four times. Then, open the Switch's Bluetooth settings and pair your controller. If it worked, the LED light on the 8Bitdo controller will be solid blue.
Because the 8Bitdo controllers don't have HD rumble, a six-axis accelerometer, or motion controls, it won't work properly with certain games. It also doesn't support Amiibo connecting. The retro controllers are best played with classic Nintendo game, like the long list of NeoGeo titles you can get in the eShop right now, or the upcoming promised titles Nintendo has yet to release.