If you need to type numbers really fast, of course there’s no beating numlock. 10 key for the win. Of course that doesn’t get at why not just leave it as 10 key forever and skip the arrows. I know a lot of older programs… like msdos older…required the use of the arrow keys. And some people do prefer it for their cursor, and it doesn’t hurt to provide the option.
You definitely don’t even need to include sex or race as an input for the AI to show bias. AI can find other things that tend to show sex or race… perhaps your school, perhaps your address, or perhaps the very style you tend to write in for your cover letter.