I used AmEx for the original 5k deposit, but I don't think I got any cash back. Don't places like Costco/Sams club negotiate with CC companies for special rates, but then cash back/bonus things don't work with them.
for those of us reserving 1-2 years ago, tesla could have made more than 2-3% in interest, or at least more than 2-3% in value of not having to raise that cash some other way. [excluding those of us from WA state where the money is locked up somewhere]