Offer your insights or judgment on the input financial query or topic using your financial expertise. Reply as normal question answering

Why are bank transactions not instant?
If you want your bank to pay $1 to a beneficiary Bob, then the service (no matter how implemented) needs to result in Bob's bank saying to Bob "Hey, I owe you $1".    The usual way how this is done consists of two parts - your bank needs to somehow tell Bob's bank "hey guys, do us a favor and please give Bob $1 with a message from the sender", and your bank needs to convince the other bank that they'll pay for (cover) that. This is the main source for the delays in international payments - there are thousands of banks, and most of possible pairs have no legal contact between themselves whatsoever, no bilateral agreements, no trust and no reasonable enforcement mechanism for small claims. If I'm Bob's bank, then a random bank from anywhere from Switzerland to Nigeria can send me an instruction "give Bob $1, we'll make it up for you", the SWIFT network is a common way of doing this. However, most likely I'm going to give Bob the money only after I receive the funds somehow, which means that they have given the money to some institution I work with. For payments within a single country, it often is a centralized exchange or a central bank, and the payment speed is then determined by the details of that particular single payment network - e.g. UK Faster Payments or the various systems used in USA. For international payments, it may require a chain of multiple intermediaries (correspondent banks) - for example, a payment of $1mm from Kazakhstan to China will likely involve the Kazakhstan bank asking their main correspondent in USA (some major bank such as Chase JPMorgan) to give the money to the relevant chinese bank's correspondent in USA (say, Citi) to then give the money to that chinese bank to then give the money to the actual recipient. Each of those steps can happen because those entities have bilateral agreements, trust and accounts with each other; and each of those steps generally takes time and verification. If you want all payments to happen instantly, then you need all institutions to join a single binding payment system. It's not as easy as it sounds, as it is a nightmare of jurisdiction - for example, if you'd want me (as Bob's bank) to credit Bob instantly, then the system needs to provide solid guarantees that I would get paid even if (a) the payer institution changes its mind, made a mistake or intentional fraud; (b) the payer institution goes insolvent; (c) the system provider gets insolvent. Providing such guarantees is expensive, they need to be backed by multi-billion capital, and they're unrealistic to enforce across jurisdictions (e.g. would an Iranian bank get recourse if some funds got blocked because of USA sanctions). The biggest such project as far as I know is SEPA, across most of Europe. Visa and MasterCard networks perform the same function - a merchant gets paid by the CC network even if the payer can't pay his CC bill or the paying bank goes insolvent.