I know USB booting on pi is still not perfect, but it almost seems to make more sense at this point to boot off of a decent USB flash drive, I would think? If you get a decent brand with good benchmarks, I would think that reads/writes would blow all SD cards away. What I'm not sure about is latency or lifespan, though I would think _good_ USB flash drives are likely to be better quality flash than SD, without really being significantly costly in comparison?
I say this as someone that uses SD cards currently, and I understand if others do also- it's the easiest/default option, but I've definitely given thought to switching
USB flash drives are mostly just as bad. Many advertise large read/write numbers but they overwhelmingly all hit a wall once the MB or two of cache is full. And they seem to be as unreliable as SD these days.
The solution is USB->SATA SSD converters with SATA SSDs. Those will easily sustain a few hundred MB/sec read/write. The problem then becomes the USB inefficiencies, but for the most part wear leveling/etc make them pretty bullet proof.
The PFTF UEFI firmware will reliably boot off just about everything you can plug in (USB DVD/etc included).
I've had a USB flash drive failed after only 3 months in the Raspberry Pi before, so now I'm using a SATA-USB cable with a SSD drive, looking good so far.
I say this as someone that uses SD cards currently, and I understand if others do also- it's the easiest/default option, but I've definitely given thought to switching