[numpad0]

People are going to ignore that and leave bad reviews online, which will have compounding effects. SMR drives works in RAID until CMR buffer regions are depleted, and then RAID starts falling apart. This will undoubtedly create wrong impressions that Synology products, not the drives, are not trustworthy.

[Melatonic]

What if the device had a minimum benchmark feature that would test any new drive ? And fail the worst ones ?

[numpad0]

SMR drives work like SSD: writes are buffered to CMR zone, consolidated into an SMR track data, copied into onboard cache RAM and written to SMR zone. SMR tracks has sizes of 128MB or so, and can be written or erased in track-at-once manners by the head half-overwriting data like moving a broad whiteboard marker slowly outward on a pottery wheel, rather than giving each rings of data enough separation. This works because the heads has higher resolution in radial direction in reads than writes; the marker tip is broader than what the disk's eyes can see.

This copy operation is done either while the disk is idling, or forced by stop responding to read and write operations if CMR buffer zone is depleted and data has to be moved off. RAID softwares cannot handle the latter scenarios, and consider the disk faulty.

You can probably corner a disk into this depleted state to expose a drive being SMR based, but I don't know if that works reliably or if it's the right solution. This is roughly all I know on technical side of this problem anyway.