Why not simply say donation
It’s about setting expectations. The wording is chosen because they believe that paying open source developers for their work should be the norm, not the exception. Calling it a donation would not do that justice. Their wording is saying “Here’s the software, we’ll trust you to pay us for it if it brings you value and you can afford it”. It’s an explicit expectation to pay, unless you have good reasons not to, which is also fine but should be the exception. Whereas a donation is very much optional and not the default expectation by nature.
In the end it’s just a semantic difference, it’s just all about making expectations clear even if there is no enforcement around them.
If you have a USB C to C cable handy, that’s also going to work to charge other devices, loses less power to the transfer, is quicker, and also more convenient since you can keep using both phones. Of course you’ll often not have a cable, but if you do it’s probably gonna be the better option