I wouldn't call the wire transfers exactly instant (perhaps it depends on the bank?), but they should be at least same-day in most cases if you're doing an online wire transfer.

The main problem is that most services that accept a wire transfer might take a while to verify your bank transfer and will often not verify bank transfers outside business hours, so they're not quite as perfect as I would want them to be. If the bank systems could only have been upgraded to support including a reference number, or better yet provide a system for automatic verification by the submitter (such as a request link + verification link, tokens, QR code)... But I'm dreaming about change to some very old systems.