My view is always that it is a reduction of cost and a refund for that reduction. If it was a business trip, reduce the cost. If it was a pleasure trip, who cares. Points are a refund for the expense of the products or survives received. 

The Bonus Points for signing on probably should be like the toaster's given out by the banks last century. Originally a nice free bonus, but then IRS said it was taxable and the bank issued a 1099. I don't think 1099s are issued for Points., but . . . .I think Points for travel or purchases using the card are a reduction or rebate on the items purchased, meaning not an income, but if used in a business you  should reduce the cost of the item purchased. 

In your case, I would take it to be the cost of taking care of my self during the hours that were unscheduled and not an income.