Originally Posted by itsme
But do the double miles offers (UA Visa and SPG AmEx) apply to the payment of state taxes, or only to federal ones? If there are not to be double miles for use of the card to pay, then the miles will come at a cost of 2 cpm or more, which is not too appealing, at least to me. (Are other card issuers besides UA Visa and SPG AmEx offering double miles or other special incentives to use them?)
I didn't get into that, since the question to which I responded didn't ask that.
I suspect, though I do not have specific information, that these bonuses are handled the same way most such bonuses are. Merchants are coded as to whether they're supermarkets, gas stations, or in this case third-party tax payment services. The credit card company then applies the bonus to all charges to appropriately coded merchants. If the usual method is used, and I doubt any CC issuer would have gone to the trouble of coming up with a totally new way to handle bonuses for this, then double miles offers would apply here as well.
Specific information would have to come from each CC issuer individually.