Button-button GPIO9 ?

It looks like SW1 (The "Button" button) pulls down GPIO9 when pressed.

According to this: https://tech.scargill.net/esp8266-dio-mysteries-solved/, any pull-down on GPIO9 (even through software) will reset the ESP. This is what I noticed as well; pressing the button initiates a reset.

Is there any rationale behind this connection? Or would it be a good idea to redesign with SW1 connected to GPIO2 (currently unconnected)? That way the button could be used in programming.