We should help users avoid making mistakes. The reset button may delete important recipes or packages and, as a consequence, users won't be able to create any image. The button should be removed.
http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=1dd648e9419501b911cd1d9a0d335ff3cfc8683a
I checked the latest Hob, and the button has been removed. Thanks