I suspect the flash storage can’t sustain 60MB/sec writes indefinitely…
The iPhone line has used NVMe drives for a decade. Even the iPhone X can do sustained writes of over 100MB/sec.
The amazonbasics 256GB microsd is faster than that. I really doubt the flash in an iPhone is worse.
And the speed you should actually expect from USB 2.0 is more like 35MB/s so that's even easier for flash to handle.
The iPhone line has used NVMe drives for a decade. Even the iPhone X can do sustained writes of over 100MB/sec.
The amazonbasics 256GB microsd is faster than that. I really doubt the flash in an iPhone is worse.
And the speed you should actually expect from USB 2.0 is more like 35MB/s so that's even easier for flash to handle.