@Hulex It does two main things:

1) Let you use these controllers on a Switch: PS4, PS3, Wii U Pro, Xbox One, Xbox 360, and many standard wired USB controllers like ones by Logitech
2) Lets you use these controllers on a PC or PS3: the above, plus Switch Pro and Switch Joy-Cons.

It does seem to support wireless connections but I haven't tested that yet. On the PS4 pad, all buttons work, including the gryo, home, and share button

@Hulex (though you hit the touch pad to snap a sceenshot and the "share" button for minus)

@ShugoWah As far as I can tell it's not adding any lag on buttons or analog movement. I ran Dead Cells level 1 in 1m 06s on a PS4 arcade stick

@ShugoWah If there's a particular thing you want me to test out lemme know!

@ShugoWah On the XB1 pad, - is view (the "select" button), + is menu (the "start" button), home is home, and capture is view+menu

@ShugoWah Also worth noting that it maps the face buttons based on position rather than label (so the Xbox's green "A" is the switch's B)

@ShugoWah There's not much really; it just changes what kind of connection it emulates for the Switch. "You have a Switch Pro controller plugged in" vs "You have a Switch Pro controller connected wirelessly." Probably just for compatability/futureproofing? Not sure if there's any performance difference

@ShugoWah yeah. TBH the pro is a solid controller, it's just got a premium price. (and is really only necessary if at this very moment you are a speed runner or Splatoon 2 esporter)

I got the adapters for nerd games at parties because yikes1 those nintendo controller options are pricey and yikes2 some games are very awkward with a single sideways joycon

@ShugoWah (if you want an example of what I mean, try playing the Nine Parchments demo from the eShop with just one joycon! :3 )

@ShugoWah Follow up: the PS4's gyro only works in purple mode, it's disabled in red mode

@ShugoWah the red mode is probably also included since it requires no setup from the system side. (You gotta flip a setting for purple mode that also turns off amiibo reading)