Both the TXS0206 A and non-A SD level shifting devices have internal pull ups for the CD and WP switches on a SD card socket.
The datasheets for TXS0206 A and non-A version of these parts show reference circuits for interfacing to SD card sockets.
In the TXS0206 datasheet this is Figure 1. http://www.ti.com/lit/gpn/txs0206 This reference circuit shows routing the WP switch to the WP pin on the TXS0206 device.
The TXS0206A datasheet(which is newer than the TXS0206 datasheet) shows reference circuits for SD sockets both with and without the WP switch. Figure 1 and Figure 2
http://www.ti.com/lit/gpn/txs0206a
What is interesting here in Figure 2 is the internal TXS0206A WP pull up is not used and instead the SD card socket WP switch is pulled up external to the device. This design choice is not explained.
Why was this choice made in the reference circuit of the A version of this part and not the non-A version?
What are the reasons I would choose to use or not use the internal CD and WP pull-ups of either device?