My wife upgraded from what I believe was an iPhone 11 to an iPhone 14 Pro and chose to have the setup done in an Apple Store. The employee used a MacBook during the process and said it would make the transfer go faster because it was taking a while. This happened in the middle of the store during a busy period, with plenty of people around. I assumed the phones would be transferred directly, so I've been wondering ever since whether using a store computer was normal or whether I'm being unnecessarily paranoid.
2 Answers
Employees normally shouldn’t back up a customer’s phone to a shared or temporary store Mac. It’s possible the computer was only being used for an update or another setup task, but transferring a full backup through it would not be the standard approach. Since this happened openly during a busy period, malicious access seems unlikely, though checking the new phone and changing important account passwords can provide peace of mind.
The usual fastest method is a direct phone-to-phone transfer using a cable, especially if there isn’t an iCloud backup to restore. A Mac generally shouldn’t be needed to move the contents from one iPhone to another. It may have been used to update iOS or help with setup, but that’s different from storing a customer’s backup on the computer.

That makes sense. I mainly wanted to know whether using a Mac for the transfer was standard, since the employee specifically said it would speed things up.