Where did you find information about the ID_USB_TYPE==‘disk’?
Searching on the web, or on man pages with man --global-apropos ID_USB_TYPE does not return a result on it.
Also, what about USB connected HDD docks? Does this apply to them too?
It is part of environment variables set by udev when a device is registered.
Please see the Arch Wiki on udev - especially see the links in the See Also section.
You can use udevadm to retrieve the information.
You can check - plug your device - then note the device path
udevadm test /dev/<device>