What's really hindering responsiveness and day-to-day performance isn't going to be sequential read and write speeds but rather 4K random IOPS.
SD cards are not all designed or optimized around small, random reads and writes - the typical workload of a boot drive - and latencies can be staggering. Similar for USB sticks. On the other hand, these days the overwhelming majority of M.2 SSDs are at least somewhat optimized for 4K IOPS. The latest Sabrent Rocket M2 SSDs get some 650,000 4K IOPS vs eMMC at ~13000 (the Rocket is 50X faster) an SD card around ~2000 (the Rocket is 325X faster).
Frankly if you stuck a Sabrent Rocket on a PCIe 1.0 x1 connector the performance would absolute savage an SD or eMMC solution on this workload. Even if they somehow also had identical sequential I/O specs.
SD cards are not all designed or optimized around small, random reads and writes - the typical workload of a boot drive - and latencies can be staggering. Similar for USB sticks. On the other hand, these days the overwhelming majority of M.2 SSDs are at least somewhat optimized for 4K IOPS. The latest Sabrent Rocket M2 SSDs get some 650,000 4K IOPS vs eMMC at ~13000 (the Rocket is 50X faster) an SD card around ~2000 (the Rocket is 325X faster).
Frankly if you stuck a Sabrent Rocket on a PCIe 1.0 x1 connector the performance would absolute savage an SD or eMMC solution on this workload. Even if they somehow also had identical sequential I/O specs.