basically does the joy-con charging grip allow for usb controller connection if you plug it directly into the console, or is it just bluetooth still? otherwise, is there a way to get a wired connection using joy-cons over usb?
They do not fit, and it also does not make it appear as a wired controller. It is strictly for chargingHori made a grip for the Split Pad Pro that turned them into a wired controller. But it might not work with regular joycon.
Hori Split Pad Attachment working with other joycon.
They do not fit, and it also does not make it appear as a wired controller. It is strictly for charging
The Hori Split Pad Pro/Compact cannot be charged, as they don't have a battery in them. The whole point of the Attachment was to be able to use them in docked mode, by connecting them with a wire.
But you are right about it not working with other controllers - a comment on asked about using the Nyxi Wizards with it, and it seems they will physically fit (as all joycon have to use the same rail in order to fit onto the Switch itself), but won't communicate with it.
Maybe it would work with sys-con, or if not maybe support could be added?there seem to be a number of claims on reddit that the charging grip does support usb inputs on some devices like the steam deck (but not on android) and notably not on the switch itself. this isn’t helpful for my use-case (with the switch) but maybe if someone else sees this thread they can use this info.