Has Apple blocked keyboard makers from using the Smart Connector on iPad Pro 3? All 3rd-party keyboards for iPP3 are using Bluetooth, which does not have a good security track record. Apple's iPad Pro keyboard does not have backlighting, media keys or good key travel.
For iPad Pro 1 and 2, Logitech made good external keyboards with media keys and backlighting, using the Smart Connector (no Bluetooth).
On iPad (regular) and Air, Apple's keyboard has a magnetic connector at the bottom of the iPad, which has the ability to remotely enable (?!) Bluetooth, even if the user has turned it off. No onscreen prompt is given to the user to let them know that Bluetooth was turned on at the time of keyboard magnetic attachment.