Usually I'll let the points sit and use them when I have to travel - so the points never touch my bank accounts. I'm not a tax expert, but for that reason I don't bother reporting any income on it
Travel status/miles are sort of similar. It’s a basic racket: the airline rewards you for steering your company’s money to them. It seems to be broadly acceptable but I agree looks pretty sketchy when you boil it down to the basics.
But if the business spends $100 and the rebate is $2, but I personally pocket the rebate instead of giving the money back to the business, wouldn't that $2 become taxable personal income? (and perhaps also theft, depending on my relationship to the business?)
If you run a small business and have a SB card, spending just $100k can get you more than $1k in rewards a year. $1k is still probably not worth the IRS tracking down, but getting on the IRS being too busy to tackle your tax fraud is still tax fraud.