I recently got the AMEX Business Platinum as well with a 150,000 point sign up bonus. I applied my $200 travel credit on AA and bought five 500-mile upgrades last month and plan to buy 5 more this year. I am Executive Platinum (got it free through Hyatt in 2019 and it keeps getting extended) and I will use these to upgrade my wife when we fly together. I don't tend to use points for cash because I can usually get a better return with just transferring the points, but if you plan to do that, then AA sounds like it makes sense if you fly them most of the time.