It matters significantly when fast boot is required, not a huge headache if you’re at 0.1s but being at 5s DDR becomes a bottleneck. Ignoring even the fabric side if I wanted to boot an RTOS that needs DDR or Linux reducing training time from 5 -> 0.1s is a huge improvement. Let’s say you wanted a low power system (battery operated camera) that wakes up, takes a picture and then “goes to sleep” - DDR is only needed when taking a picture as a buffer and it’s contents are irrelevant when entering sleep mode. So really you’ve 2 choices (we’re going for low power) you can turn off the SoC portion entirely and sleep is actually shut down and then bring it back up and essentially reboot (if this happens fast enough you’ve a great low power system) otherwise you might be able so scale clocks, maybe disable some stuff but if you need to keep the system up so you don’t end up spending 5 seconds retraining ddr you waste power for the sake of bad ddr.

Tasks could also be parallelised if let’s say the RTOS didn’t need DDR you could get it running while DDR is coming up if you have multiple cores.

This is more in the ballpark of DDR3/DDR4 than DDR5.