Also a jeweler’s screwdriver of a certain size can be used on the security fasteners. The screw is M2-.4. A 2mm screw. I picked up some at one of the big box stores, very inexpensive. The Bay also has many options.
Not sure why the security screws are used, but like an Allen head, they are visually appealing.
By the way, when the DIY case is sold as a standalone, it comes with a driver for the TA security bit.
Khadas offers a fastener kit with the driver.