I wouldn’t be so sure about that. In some payment situations you’re asked whether you’d like to have the transaction go through as debit or as credit—so those two must be different somewhere. And probably in more than just a bit in a packet, as, for example, paying with debit Visas or MasterCards (normal ones, not Electron resp. Maestro) in the Netherlands (where locals almost universally have credit cards) is something of a crapshoot.
Some payment providers ask up front to simplify the flows as it's not totally trivial to determine what sort of card it is, and also because different fees apply - historically some merchants added specific fees to basket etc. (less so nowadays but the UI convention sticks)
And because the same card can be both. At least here in Brazil, most bank cards have multiple uses (credit, debit, ATM) in the same card. AFAIK, they're separate applications within the same chip, and the terminal has to select which one to use before starting.
The BIN will tell you which bank was the issuer and which class of card you have, like standard or premium, though most readers probably don't take that into account beyond the card scheme and card type associated with the range that the individual BIN is in. Many banks will have multiple BINs for the same card type if they are large.
Credit / online debit / offline debit usually get different ranges. The reader gets a list of the ranges when it updates and they don't change super often. Offline readers can be configured to reject cards with a number in an online only range.
Before that, there was the service code on the magnetic stripe, which also can convey things like "online only" or "domestic use only".
The BIN is only involved in risk management on the terminal's side: Many of these in-flight terminal accept deferred online transactions, which means that, even though they're completely offline, they take the risk of accepting an online-only card. (For truly offline capable cards, the risk is often with the issuing bank.)
That type of risk management can benefit from knowing what type of card it is, and prepaid cards are often seen as riskier (because customers might intentionally drain them before a flight). Of course, debit and credit cards can also be empty/marked as stolen, but these are marginally harder to get and replace.
Your correct on the risk spread. I wasn't confident last night (I'm not totally versed on the terminals) but looked it up. As I understand if you choose to accept offline only payments then you accept the risk of the transaction failing. If it's the issuers choice they own the risk.
Nope, even this is identical. These days the difference between a debit/credit card is pretty much aesthetic, from a transaction processing perspective there generally isn’t any actual differences. Differences that people see today are most artificial for the purpose of justifying extra fees, or higher interchange based an entirely arbitrary factor that has zero correlation to any risks that appear in the transaction processing and clearing mechanisms.
Basically the only reason anyone really bothers keeping the difference between credit/debit cards around, is as a technical excuse for discrimination and abusive fees. Notably in the EU nobody cares if a debit or credit card is used, because the EU outlawed all the crazy fees and other bullshit, so now there’s no commercial reason to differentiate between the two 99% of the time.
But to your wider point; from a transaction fee point of view you are dead right. Of course a credit card has other attractions; for example it's credit :D but also things like section 75 protection.
From the perspective of the card network and the merchant, there is no difference here. The card network has a contract with the issuer, so all transactions, in all scenarios, are always first paid by the issuer. It’s then the issuers problem to figure out where they get the money from.
It’s entirely possible to perform transactions on debit card that will place the account attached to it in a negative balance, and for the person owning that account to vanish. The card issuer is still on the hook for the money, neither the card network, nor the merchant, care if the issuer recovers the funds or not, they always get paid.
> I wouldn’t be so sure about that.
I would be very sure about that.
> In some payment situations you’re asked whether you’d like to have the transaction go through as debit or as credit—so those two must be different somewhere
Yes, that is correct.
